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The Origins of Viruses

The evolutionary history of viruses represents a fascinating, albeit murky, topic for virologists and cell biologists. Because of the great diversity among viruses, biologists have struggled with how to classify these entities and how to relate them to the conventional tree of life. They may represent genetic elements that gained the ability to move between cells. They may represent previously free-living organisms that became parasites. They may be the precursors of life as we know it.

The Basics of Viruses

We know that viruses are quite diverse. Unlike all other biological entities, some viruses, like poliovirus, have RNA genomes and some, like herpesvirus, have DNA genomes. Further, some viruses (like influenza virus) have single-stranded genomes, while others (like smallpox) have double-stranded genomes. Their structures and replication strategies are equally diverse. Viruses, do, however, share a few features: First, they generally are quite small, with a diameter of less than 200 nanometers (nm). Second, they can replicate only within a host cell. Third, no known virus contains ribosomes , a necessary component of a cell's protein-making translational machinery.

Are Viruses Alive?

Do viruses conform to these criteria? Yes and no. We probably all realize that viruses reproduce in some way. We can become infected with a small number of virus particles — by inhaling particles expelled when another person coughs, for instance — and then become sick several days later as the viruses replicate within our bodies. Likewise we probably all realize that viruses evolve over time. We need to get a flu vaccine every year primarily because the influenza virus changes, or evolves, from one year to the next (Nelson & Holmes 2007).

Viruses do not, however, carry out metabolic processes. Most notably, viruses differ from living organisms in that they cannot generate ATP . Viruses also do not possess the necessary machinery for translation , as mentioned above. They do not possess ribosomes and cannot independently form proteins from molecules of messenger RNA . Because of these limitations, viruses can replicate only within a living host cell. Therefore, viruses are obligate intracellular parasites. According to a stringent definition of life, they are nonliving. Not everyone, though, necessarily agrees with this conclusion. Perhaps viruses represent a different type of organism on the tree of life — the capsid-encoding organisms, or CEOs (Figure 1; Raoult & Forterre 2008).

Where Did Viruses Come From?

There is much debate among virologists about this question. Three main hypotheses have been articulated: 1. The progressive, or escape, hypothesis states that viruses arose from genetic elements that gained the ability to move between cells; 2. the regressive, or reduction, hypothesis asserts that viruses are remnants of cellular organisms; and 3. the virus-first hypothesis states that viruses predate or coevolved with their current cellular hosts.

The Progressive Hypothesis

Retroviruses have a single-stranded RNA genome. When the virus enters a host cell, a viral enzyme , reverse transcriptase , converts that single-stranded RNA into double-stranded DNA. This viral DNA then migrates to the nucleus of the host cell. Another viral enzyme, integrase , inserts the newly formed viral DNA into the host cell's genome. Viral genes can then be transcribed and translated. The host cell's RNA polymerase can produce new copies of the virus's single-stranded RNA genome. Progeny viruses assemble and exit the cell to begin the process again (Figure 2).

This process very closely mirrors the movement of an important, though somewhat unusual, component of most eukaryotic genomes: retrotransposons. These mobile genetic elements make up an astonishing 42% of the human genome (Lander et al . 2001) and can move within the genome via an RNA intermediate. Like retroviruses, certain classes of retrotransposons, the viral-like retrotransposons, encode a reverse transcriptase and, often, an integrase. With these enzymes, these elements can be transcribed into RNA, reverse-transcribed into DNA, and then integrated into a new location within the genome (Figure 3). We can speculate that the acquisition of a few structural proteins could allow the element to exit a cell and enter a new cell, thereby becoming an infectious agent. Indeed, the genetic structures of retroviruses and viral-like retrotransposons show remarkable similarities.

The Regressive Hypothesis

In contrast to the progressive process just described, viruses may have originated via a regressive, or reductive, process. Microbiologists generally agree that certain bacteria that are obligate intracellular parasites, like Chlamydia and Rickettsia species , evolved from free-living ancestors. Indeed, genomic studies indicate that the mitochondria of eukaryotic cells and Rickettsia prowazekii may share a common, free-living ancestor (Andersson et al . 1998). It follows, then, that existing viruses may have evolved from more complex, possibly free-living organisms that lost genetic information over time, as they adopted a parasitic approach to replication.

Viruses of one particular group, the nucleocytoplasmic large DNA viruses (NCLDVs), best illustrate this hypothesis. These viruses, which include smallpox virus and the recently discovered giant of all viruses, Mimivirus, are much bigger than most viruses (La Scola et al . 2003). A typical brick-shaped poxvirus, for instance, may be 200 nm wide and 300 nm long. About twice that size, Mimivirus exhibits a total diameter of roughly 750 nm (Xiao et al . 2005). Conversely, spherically shaped influenza virus particles may be only 80 nm in diameter, and poliovirus particles have a diameter of only 30 nm, roughly 10,000 times smaller than a grain of salt. The NCLDVs also possess large genomes. Again, poxvirus genomes often approach 200,000 base pairs, and Mimivirus has a genome of 1.2 million base pairs; while poliovirus has a genome of only 7,500 nucleotides total. In addition to their large size, the NCLDVs exhibit greater complexity than other viruses have and depend less on their host for replication than do other viruses. Poxvirus particles, for instance, include a large number of viral enzymes and related factors that allow the virus to produce functional messenger RNA within the host cell cytoplasm .

Because of the size and complexity of NCLDVs, some virologists have hypothesized that these viruses may be descendants of more complex ancestors. According to proponents of this hypothesis, autonomous organisms initially developed a symbiotic relationship. Over time, the relationship turned parasitic, as one organism became more and more dependent on the other. As the once free-living parasite became more dependent on the host, it lost previously essential genes. Eventually it was unable to replicate independently, becoming an obligate intracellular parasite, a virus. Analysis of the giant Mimivirus may support this hypothesis. This virus contains a relatively large repertoire of putative genes associated with translation — genes that may be remnants of a previously complete translation system. Interestingly, Mimivirus does not differ appreciably from parasitic bacteria, such as Rickettsia prowazekii (Raoult et al . 2004).

The Virus-First Hypothesis

Most biologists now agree that the very first replicating molecules consisted of RNA, not DNA. We also know that some RNA molecules, ribozymes, exhibit enzymatic properties; they can catalyze chemical reactions. Perhaps, simple replicating RNA molecules, existing before the first cell formed, developed the ability to infect the first cells. Could today's single-stranded RNA viruses be descendants of these precellular RNA molecules?

Others have argued that precursors of today's NCLDVs led to the emergence of eukaryotic cells. Villarreal and DeFilippis (2000) and Bell (2001) described models explaining this proposal. Perhaps, both groups postulate, the current nucleus in eukaryotic cells arose from an endosymbiotic-like event in which a complex, enveloped DNA virus became a permanent resident of an emerging eukaryotic cell.

No Single Hypothesis May Be Correct

Where viruses came from is not a simple question to answer. One can argue quite convincingly that certain viruses, such as the retroviruses, arose through a progressive process. Mobile genetic elements gained the ability to travel between cells, becoming infectious agents. One can also argue that large DNA viruses arose through a regressive process whereby once-independent entities lost key genes over time and adopted a parasitic replication strategy. Finally, the idea that viruses gave rise to life as we know it presents very intriguing possibilities. Perhaps today's viruses arose multiple times, via multiple mechanisms. Perhaps all viruses arose via a mechanism yet to be uncovered. Today's basic research in fields like microbiology, genomics , and structural biology may provide us with answers to this basic question.

Contemplating the origins of life fascinates both scientists and the general public. Understanding the evolutionary history of viruses may shed some light on this interesting topic. To date, no clear explanation for the origin(s) of viruses exists. Viruses may have arisen from mobile genetic elements that gained the ability to move between cells. They may be descendants of previously free-living organisms that adapted a parasitic replication strategy. Perhaps viruses existed before, and led to the evolution of, cellular life. Continuing studies may provide us with clearer answers. Or future studies may reveal that the answer is even murkier than it now appears.

References and Recommended Reading

Andersson, S. G. E. et al . The genome sequence of Rickettsia prowazekii and the origin of mitochondria. Nature 396 , 133–143 (1998) doi:10.1038/24094.

Bell, P. J. L. Viral eukaryogenesis: Was the ancestor of the nucleus a complex DNA virus? Journal of Molecular Evolution 53 , 251–256 (2001) doi:10.1007/s002390010215.

Koonin, E. V. & Martin, W. On the origin of genomes and cells within inorganic compartments. Trends in Genetics 21 , 647–654 (2005).

Lander, E. S. et al . Initial sequencing and analysis of the human genome. Nature 409 , 860–921 (2001) doi:10.1038/35057062.

La Scola, B. et al . A giant virus in Amoebae. Science 299 , 2033 (2003) doi:10.1126/science.1081867.

Nelson, M. I. & Holmes, E. C. The evolution of epidemic influenza. Nature Reviews Genetics 8 , 196–205 (2007) doi:10-1038/nrg2053.

Prangishvili, D., Forterre, P. & Garrett, R. A. Viruses of the Archaea: A unifying view. Nature Reviews Microbiology 4 , 837–848 (2006) doi:10.1038/nrmicro1527.

Raoult, D. & Forterre, P. Redefining viruses: Lessons from mimivirus. Nature Reviews Microbiology 6 , 315–319 (2008) doi:10.1038/nrmicro1858.

Raoult, D. et al . The 1.2-megabase genome sequence of Mimivirus. Science 306 , 1344–1350 (2004) doi:10.1126/science.1101485.

Villarreal, L. P. & DeFilippis, V. R. A hypothesis for DNA viruses as the origin of eukaryotic replication proteins. Journal of Virology 74 , 7079–7084 (2000).

Xiao, C. et al . Cryo-electron microscopy of the giant Mimivirus. Journal of Molecular Biology 353 , 493–496 (2005) doi:10.1016/j.jmb.2005.08.060.

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What is the Point of Reduction in Science?

• Original Research
• Published: 30 November 2018
• Volume 85 , pages 1437–1460, ( 2020 )

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• Karen Crowther   ORCID: orcid.org/0000-0003-1558-4814 1  

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The numerous and diverse roles of theory reduction in science have been insufficiently explored in the philosophy literature on reduction. Part of the reason for this has been a lack of attention paid to reduction 2 (successional reduction)—although I here argue that this sense of reduction is closer to reduction 1 (explanatory reduction) than is commonly recognised, and I use an account of reduction that is neutral between the two. This paper draws attention to the utility—and incredible versatility—of theory reduction. A non-exhaustive list of various applications of reduction in science is presented, some of which are drawn from a particular case-study, being the current search for a new theory of fundamental physics. This case-study is especially interesting because it employs both senses of reduction at once, and because of the huge weight being put on reduction by the different research groups involved; additionally, it presents some unique uses for reduction—revealing, I argue, the fact that reduction can be of specialised and unexpected service in particular scientific cases. The paper makes two other general findings: that the functions of reduction that are typically assumed to characterise the different forms of the relation may instead be understood as secondary consequences of some other roles; and that most of the roles that reduction plays in science can actually also be fulfilled by a weaker relation than (the typical understanding of) reduction.

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Richer Than Reduction

Big Ideas: The Power of a Unifying Concept

The First Specific Abstractive Reduction in Seebohm’s Theory of Science

Cf. Dawid ( 2013 ), Huggett and Wüthrich ( 2013 ) and Woit ( 2006 ).

The vagueness introduced by the “in principle” aspect of this definition is due to our inability in practice of actually going through and obtaining all of the results of the new theory in the old domain (due, e.g., to lack of computing power). Instead, the point is that we obtain enough ‘linkages’ (which I define below as ‘correspondence relations’) between the two theories that we believe (i.e., scientific consensus holds that) they approximately share the same results in this domain.

As evidence of this, consider the Stanford Encyclopedia of Philosophy entry on scientific reduction (van Riel and Van Gulick 2016 , §2.1), which briefly mentions, then dismisses this form of reduction as outside its area of interest.

This is in contrast this with reduction 1 , whose aim is commonly taken as the explanation of higher-level laws (behaviour, theories, fragments of theories, models, etc.) in terms of lower-level ones.

This is often referred to as the physicists’ convention , since it is how the term “reduction” is understood by physicists—the newer, more general, or more fundamental, theory, N reduces to the older, more restricted, or less fundamental theory, O . In contrast, the philosopher’s convention has O reduce to N .

Wimsatt ( 1976 , p. 680) conceives of levels of organisation as “primarily characterized as local maxima of regularity and predictability in the phase space of different models of organization of matter”.

This is recognised in the case of reduction 2 , at least (Nickles 1973 ; Wimsatt 1976 ).

See Sect.  3 .

Although limiting relations are involved in derivations, they—strictly speaking—can only establish that solutions of the new equations coincide with solutions of the old equations in the limit (Hüttemann and Love 2016 , p. 468).

The various correspondence relations between quantum and classical mechanics are explored, e.g., in Radder ( 1991 ), Bokulich ( 2008 ); that these are insufficient to establish that classical mechanics is ‘contained within’ quantum mechanics, is argued in, e.g., Post ( 1971 ).

The correspondence principle was famously proposed by Niels Bohr in the context of old quantum theory, yet the common understanding of the principle is most certainly not what Bohr meant by it (Bokulich 2014 ).

Note that this is an original formulation, and thus differs from Post’s ( 1971 ) GCP.

Note that the theories need not be compatible in any other sense!

Whether the relations can actually achieve any of these roles in any particular real scientific case, depends on many factors, most of which will be case-specific. I do not explore these here.

See fn. 15.

Definition from Hoyningen-Huene ( 1993 , p. 260).

This section draws heavily from Crowther ( 2018 ), please refer to this for more details.

See, respectively: Polchinski ( 1998a , b ), Rovelli ( 2004 ) and Rovelli and Vidotto ( 2014 ), Henson ( 2009 ), Ambjorn et al. ( 2012 ), Oriti ( 2012 ).

Accessible introductions to QG include Kiefer ( 2006 ), Rickles ( 2008 ).

Cf. Norton ( 2003 ).

See, e.g., Collins et al. ( 2009 ) and Liberati and Maccione ( 2011 ).

This is related also to the issue of emergence , cf. Crowther ( 2016 ) and Wüthrich ( 2017 ).

See, e.g., Dowker ( 2005 ), Oriti ( 2014 ) and Padmanabhan ( 2016 ).

This is the case, e.g., in string theory, (Polchinski 1998a , b )

Recall that derivability (which may be established using relations of correspondence which need not be asymmetric) is being used to demonstrate the asymmetric relation of reduction: i.e., that all the successful parts of the reduced theory can (approximately and appropriately) be obtained from the reducing theory. The idea of dependence, or relative fundamentality, is that the reduced theory is thus shown to be embedded within the reducing theory (and hence that the physics described by the reduced theory depends on that of the reducing theory).

Keeping in mind the qualifications regarding my use of this term, outlined on p. 3.

Ambjorn, J., Jurkiewicz, J., & Loll, R. (2004). Emergence of a 4D world from causal quantum gravity. Physical Review Letters , 93 (13), 131301.

Google Scholar  

Ambjorn, J., Jurkiewicz, J., & Loll, R. (2012). Causal dynamical triangulations and the quest for quantum gravity. In A. W. George Ellis & J. Murugan (Eds.), Foundations of space and time: Reflections on quantum gravity (pp. 321–337). Cambridge: Cambridge University Press.

Bell, J. (1987). Speakable and unspeakable in quantum mechanics . Cambridge: Cambridge University Press.

Bokulich, A. (2008). Reexamining the quantum-classical relation: Beyond reductionism and pluralism . Cambridge: Cambridge University Press.

Bokulich, A. (2014). Bohr’s correspondence principle. The Stanford Encyclopedia of Philosophy , Spring 2014. http://plato.stanford.edu/archives/spr2014/entries/bohr-correspondence/ .

Collins, J., Perez, A., & Sudarsky, D. (2009). Lorentz invariance violation and its role in quantum gravity phenomenology. In D. Oriti (Ed.), Approaches to quantum gravity: Toward a new understanding of space, time and matter (pp. 528–547). Cambridge: Cambridge University Press.

Crowther, K. (2016). Effective spacetime: Understanding emergence in effective field theory and quantum gravity . Heidelberg: Springer.

Crowther, K. (2018). Inter-theory relations in quantum gravity: Correspondence, reduction, and emergence. Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics , 63 , 74–85.

Da Costa, N., & French, S. (1993). Towards an acceptable theory of acceptance: Partial structures inconsistency and correspondence. In S. French & H. Kamminga (Eds.), Correspondence, invariance and heuristics: Essays in honour of Heinz Post volume 148 of Boston studies in the philosophy of science (pp. 137–158). Dordrecht: Springer.

Dawid, R. (2013). String theory and the scientific method . Cambridge: Cambridge University Press.

Dizadji-Bahmani, F. (2011). Neo-Nagelian reduction: A statement, defence, and application . Ph.D. thesis, The London School of Economics and Political Science.

Dizadji-Bahmani, F., Frigg, R., & Hartmann, S. (2010). Who’s afraid of Nagelian reduction? Erkenntnis , 73 (3), 393–412.

Dowker, F. (2005). Causal sets and the deep structure of spacetime. In A. Ashtekar (Ed.), 100 Years of relativity: Space-time structure (pp. 445–467). Singapore: World Scientific.

Dowker, F., Henson, J., & Sorkin, R. D. (2004). Quantum gravity phenomenology, Lorentz invariance and discreteness. Modern Physics Letters A , 19 , 1829–1840.

Friedman, M. (2001). Dynamics of reason: The 1999 Kant Lectures of Stanford University . Stanford: CSLI Publications.

Hartmann, S. (2002). On correspondence. Studies in History and Philosophy of Modern Physics , 33 (1), 79–94.

Hempel, C., & Oppenheim, P. (1948). Studies in the logic of explanation. Philosophy of Science , 15 , 135–175.

Henson, J. (2009). The causal set approach to quantum gravity. In D. Oriti (Ed.), Approaches to quantum gravity: Toward a new understanding of space, time and matter (pp. 393–413). Cambridge: Cambridge University Press.

Hoyningen-Huene, P. (1993). Reconstructing scientific revolutions: Thomas S. Kuhns philosophy of science . Chicago: University of Chicago Press.

Huggett, N., & Vistarini, T. (2015). Deriving general relativity from string theory. Philosophy of Science , 82 (5), 1163–1174.

Huggett, N., & Wüthrich, C. (2013). Emergent spacetime and empirical (in)coherence. Studies in History and Philosophy of Modern Physics , 44 (3), 276–285.

Hüttemann, A., & Love, A. (2016). Reduction. In P. Humphreys (Ed.), The Oxford handbook of philosophy of science (pp. 460–484). Oxford: Oxford University Press.

Kemeny, J., & Oppenheim, P. (1956). On reduction. Philosophical Studies , 7 (1), 6–19.

Kiefer, C. (2006). Quantum gravity: General introduction and recent developments. Annals of Physics , 15 (1), 129–148.

Kuhn, T. (1962). The structure of scientific revolutions . Chicago: University of Chicago Press.

Liberati, S., & Maccione, L. (2011). Quantum gravity phenomenology: Achievements and challenges. Journal of Physics: Conference Series , 314 , 012007.

Nagel, E. (1961). The structure of science: Problems in the logic of scientific explanation . New York: Harcourt.

Nickles, T. (1973). Two concepts of intertheoretic reduction. The Journal of Philosophy , 70 (7), 181–201.

Norton, J. (2003). General covariance, gauge theories and the Kretschmann objection. In K. Brading & E. Castellani (Eds.), Symmetries in physics: Philosophical reflections (pp. 110–123). Cambridge: Cambridge University Press.

Oppenheim, P., & Putnam, H. (1958). The unity of science as a working hypothesis. In H. Feigl, M. Scriven, & G. Maxwell (Eds.), Minnesota studies in the philosophy of science (Vol. 2, pp. 3–36). Minnesota: Minnesota University Press.

Oriti, D. (2012). The microscopic dynamics of quantum space as a group field theory. In A. W. George Ellis & Jeff Murugan (Eds.), Foundations of space and time: Reflections on quantum gravity (pp. 257–320). Cambridge: Cambridge University Press.

Oriti, D. (2014). Disappearance and emergence of space and time in quantum gravity. Studies in History and Philosophy of Modern Physics , 46 , 186–199.

Padmanabhan, T. (2016). Atoms of spacetime and the nature of gravity. Journal of Physics: Conference Series , 701 (1), 012018.

Polchinski, J. (1998a). String theory, volume 1: An introduction to the bosonic string . Cambridge: Cambridge University Press.

Polchinski, J. (1998b). String theory, volume 2: Superstring theory and beyond . Cambridge: Cambridge University Press.

Post, H. (1971). Correspondence, invariance and heuristics: In praise of conservative induction. Studies in History and Philosophy of Science Part A , 2 (3), 213–255.

Radder, H. (1991). Heuristics and the generalized correspondence principle. British Journal for the Philosophy of Science , 42 , 195–226.

Rickles, D. (2008). Quantum gravity: A primer for philosophers. In D. Rickles (Ed.), The Ashgate companion to contemporary philosophy of physics, chapter 5 (pp. 262–365). Aldershot: Ashgate.

Rosaler, J. (2017). Reduction as an a posteriori relation. British Journal for the Philosophy of Science . https://doi.org/10.1093/bjps/axx026 .

Rosenberg, A. (2006). Darwinian reductionism: Or, how to stop worrying and love molecular biology . Chicago: University of Chicago Press.

Rovelli, C. (2004). Quantum gravity . Cambridge: Cambridge University Press.

Rovelli, C., & Vidotto, F. (2014). Covariant loop quantum gravity: An elementary introduction to quantum gravity and spinfoam theory . Cambridge: Cambridge University Press.

Sánchez-Ron, J. (1983). Quantum vs. classical physics: Some historical considerations on the role played by the “principle of correspondence” in the development of classical physics. Fundamenta Scientia , 4 , 55–76.

Sarkar, S. (2015). Nagel on reduction. Studies in History and Philosophy of Science , 53 , 43–56.

Saunders, S. (1993). To what physics corresponds. In S. French & H. Kamminga (Eds.), Correspondence, invariance and heuristics: Essays in honour of Heinz Post, volume 148 of Boston studies in the philosophy of science (pp. 295–325). Dordrecht: Springer.

Scerri, E. R. (1993). Correspondence and reduction in chemistry. In S. French & H. Kamminga (Eds.), Correspondence, invariance and heuristics: Essays in honour of Heinz Post, volume 148 of Boston studies in the philosophy of science (pp. 45–64). Dordrecht: Springer.

Schaffner, K. (1967). Approaches to reduction. Philosophy of Science , xxxiv(2) , 137–147.

Schaffner, K. (1976). Reductionism in biology: Prospects and problems. In R. Cohen (Ed.), PSA 1974 (pp. 613–632). Dordrecht: D. Reidel Publishing Company.

Sklar, L. (1967). Types of inter-theoretic reduction. British Journal for the Philosophy of Science , 18 , 109–124.

van Riel, R. & Van Gulick, R. (2016). Scientific reduction. In The Stanford encyclopedia of philosophy, Spring 2016 .

Wimsatt, W. (1976). Reductive explanation: A functional account. PSA , 1974 , 671–710.

Wimsatt, W. C. (2006). Reductionism and its heuristics: Making methodological reductionism honest. Synthese , 151 (3), 445–475.

Woit, P. (2006). Not even wrong: The failure of string theory and the continuing challenge to unify the laws of physics . Cambridge: Basic Books.

Wüthrich, C. (2017). Raiders of the lost spacetime. In D. Lehmkuhl (Ed.), Towards a theory of spacetime theories (pp. 297–335). Basel: Birkhäuser.

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Acknowledgements

Thank you to my colleagues in the Department of Philosophy at the University of Geneva, as well as two referees for their helpful feedback on this paper. Funding was provided by Schweizerischer Nationalfonds (Grant No. 105212 165702).

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Crowther, K. What is the Point of Reduction in Science?. Erkenn 85 , 1437–1460 (2020). https://doi.org/10.1007/s10670-018-0085-6

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Received : 24 March 2018

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Issue Date : December 2020

DOI : https://doi.org/10.1007/s10670-018-0085-6

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That actually explain what's on your next test, reduction hypothesis, from class:, general biology i.

The reduction hypothesis is a concept in biology suggesting that the complexity of viruses can be explained by a process of simplification or loss of genetic material over time. This idea connects to the evolutionary history of viruses, positing that their current forms result from the gradual reduction of their genomes, leading to a more streamlined and efficient replication strategy. It sheds light on how viral morphology and classification can be influenced by these evolutionary changes, highlighting the relationship between a virus's structure and its functional capabilities.

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5 Must Know Facts For Your Next Test

• The reduction hypothesis suggests that viruses may have originated from more complex cellular organisms that lost genes over time as they adapted to parasitic lifestyles.
• This hypothesis helps explain why some viruses have very small genomes, as they may have shed unnecessary genes that are no longer needed in their specific environments.
• According to the reduction hypothesis, viral evolution is closely linked to their ability to rapidly mutate and adapt, leading to diverse forms and classifications.
• The reduction hypothesis also provides insights into how viral structures, like capsids and envelopes, have evolved alongside their genomic simplification.
• This concept supports the idea that studying the evolutionary history of viruses can inform our understanding of emerging viral diseases and their classifications.

Review Questions

• The reduction hypothesis explains that viruses may have evolved from more complex cellular ancestors by simplifying their genetic makeup over time. This simplification leads to reduced genome sizes and fewer functional genes, which allows viruses to efficiently replicate within host cells. As a result, understanding this hypothesis provides insights into how viral forms have changed through evolutionary processes and how they adapt to their environments.
• The reduction hypothesis implies that viral classification can be influenced by the degree of genomic reduction and corresponding morphological traits. For example, viruses with simpler structures and smaller genomes may cluster together in classifications that reflect their evolutionary history. This connection between genome size and morphology highlights how evolutionary pressures shape the characteristics of viruses and help categorize them based on observed traits.
• The reduction hypothesis could significantly impact future research by guiding scientists in understanding viral evolution and the emergence of new viral diseases. By recognizing patterns of genomic reduction and morphological changes, researchers can better predict how viruses might adapt to treatments or evade immune responses. This knowledge could lead to more effective antiviral strategies and inform public health responses to emerging infectious diseases linked to viruses.

Related terms

Genetic Drift : A mechanism of evolution that involves random changes in allele frequencies within a population, which can influence viral evolution.

Virion : The complete virus particle that consists of the genetic material encased in a protein coat, crucial for understanding viral morphology.

Horizontal Gene Transfer : The process by which organisms exchange genetic material, which can play a role in viral evolution and adaptation.

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Hypothesis Testing | A Step-by-Step Guide with Easy Examples

Published on November 8, 2019 by Rebecca Bevans . Revised on June 22, 2023.

Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics . It is most often used by scientists to test specific predictions, called hypotheses, that arise from theories.

There are 5 main steps in hypothesis testing:

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• Collect data in a way designed to test the hypothesis.
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• Present the findings in your results and discussion section.

Though the specific details might vary, the procedure you will use when testing a hypothesis will always follow some version of these steps.

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Step 1: state your null and alternate hypothesis, step 2: collect data, step 3: perform a statistical test, step 4: decide whether to reject or fail to reject your null hypothesis, step 5: present your findings, other interesting articles, frequently asked questions about hypothesis testing.

After developing your initial research hypothesis (the prediction that you want to investigate), it is important to restate it as a null (H o ) and alternate (H a ) hypothesis so that you can test it mathematically.

The alternate hypothesis is usually your initial hypothesis that predicts a relationship between variables. The null hypothesis is a prediction of no relationship between the variables you are interested in.

• H 0 : Men are, on average, not taller than women. H a : Men are, on average, taller than women.

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For a statistical test to be valid , it is important to perform sampling and collect data in a way that is designed to test your hypothesis. If your data are not representative, then you cannot make statistical inferences about the population you are interested in.

There are a variety of statistical tests available, but they are all based on the comparison of within-group variance (how spread out the data is within a category) versus between-group variance (how different the categories are from one another).

If the between-group variance is large enough that there is little or no overlap between groups, then your statistical test will reflect that by showing a low p -value . This means it is unlikely that the differences between these groups came about by chance.

Alternatively, if there is high within-group variance and low between-group variance, then your statistical test will reflect that with a high p -value. This means it is likely that any difference you measure between groups is due to chance.

Your choice of statistical test will be based on the type of variables and the level of measurement of your collected data .

• an estimate of the difference in average height between the two groups.
• a p -value showing how likely you are to see this difference if the null hypothesis of no difference is true.

Based on the outcome of your statistical test, you will have to decide whether to reject or fail to reject your null hypothesis.

In most cases you will use the p -value generated by your statistical test to guide your decision. And in most cases, your predetermined level of significance for rejecting the null hypothesis will be 0.05 – that is, when there is a less than 5% chance that you would see these results if the null hypothesis were true.

In some cases, researchers choose a more conservative level of significance, such as 0.01 (1%). This minimizes the risk of incorrectly rejecting the null hypothesis ( Type I error ).

The results of hypothesis testing will be presented in the results and discussion sections of your research paper , dissertation or thesis .

In the results section you should give a brief summary of the data and a summary of the results of your statistical test (for example, the estimated difference between group means and associated p -value). In the discussion , you can discuss whether your initial hypothesis was supported by your results or not.

In the formal language of hypothesis testing, we talk about rejecting or failing to reject the null hypothesis. You will probably be asked to do this in your statistics assignments.

However, when presenting research results in academic papers we rarely talk this way. Instead, we go back to our alternate hypothesis (in this case, the hypothesis that men are on average taller than women) and state whether the result of our test did or did not support the alternate hypothesis.

If your null hypothesis was rejected, this result is interpreted as “supported the alternate hypothesis.”

These are superficial differences; you can see that they mean the same thing.

You might notice that we don’t say that we reject or fail to reject the alternate hypothesis . This is because hypothesis testing is not designed to prove or disprove anything. It is only designed to test whether a pattern we measure could have arisen spuriously, or by chance.

If we reject the null hypothesis based on our research (i.e., we find that it is unlikely that the pattern arose by chance), then we can say our test lends support to our hypothesis . But if the pattern does not pass our decision rule, meaning that it could have arisen by chance, then we say the test is inconsistent with our hypothesis .

If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.

• Normal distribution
• Descriptive statistics
• Measures of central tendency
• Correlation coefficient

Methodology

• Cluster sampling
• Stratified sampling
• Types of interviews
• Cohort study
• Thematic analysis

Research bias

• Implicit bias
• Cognitive bias
• Survivorship bias
• Availability heuristic
• Nonresponse bias
• Regression to the mean

Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is used by scientists to test specific predictions, called hypotheses , by calculating how likely it is that a pattern or relationship between variables could have arisen by chance.

A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question.

A hypothesis is not just a guess — it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations and statistical analysis of data).

Null and alternative hypotheses are used in statistical hypothesis testing . The null hypothesis of a test always predicts no effect or no relationship between variables, while the alternative hypothesis states your research prediction of an effect or relationship.

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Being Reduced: New Essays on Reduction, Explanation, and Causation

Jakob Hohwy and Jesper Kallestrup (eds.), Being Reduced: New Essays on Reduction, Explanation, and Causation , Oxford University Press, 2008, 312pp., $90.00 (hbk), ISBN 9780199211531.

Reviewed by Steven Horst, Wesleyan University

Notions of "reduction" have been a popular topic in analytic philosophy over the past century. I say "notion s ", in the plural, because the word 'reduction' is one of those notoriously ambiguous philosophical terms of art. It can stand for a semantic relation, where a reduction of A to B is a definition of A in terms of B. It can stand for a variety of explanatory relations, particularly part-whole explanations. It can be applied to identifications of objects in different domains of discourse. Sometimes, cases in which one theory replaces another are even said to involve " eliminative reductions". To complicate matters further, the term is entwined in conversations in a number of areas of philosophy: semantics, metaphysics, philosophy of mind, philosophy of science, and ethics. Even worse, the word has made its way into popular discussions of science and philosophy, where such distinctions are sometimes blurred, lost, or neglected.

As a result, discussions of things that go by the name of "reduction" are at substantial risk of confusion or crossed-purposes. A critic of one notion of "reduction" (e.g., definitional reduction) may actually be an advocate of another (say, part-whole explanation). And a writer who is not careful to specify what notion(s) of "reduction" she is defending or criticizing risks misleading or even baffling her readers.

This volume brings together a number of original essays by prominent philosophers of mind and philosophers of science. Broadly speaking, they are all concerned with the question of what to do with the word 'reduction', but explore different notions of "reduction" which they either support or criticize. The essays are independent of one another, though they cover some common ground, and so it is not quite a conversation . However, the volume does present a more or less state-of-the-art overview of where conversations about things called "reduction" are today in philosophy. I find myself at least partly wishing it could have been a longer volume, with the contributors commenting on one another's work. Nonetheless, this is a very useful volume for professional philosophers, useful for both graduate seminars and advanced undergraduate courses in philosophy of mind, philosophy of science, and metaphysics.

Some Background

The authors of the essays in this volume are all heir to several background conversations about reduction, and it is worth saying a word or two about these conversations by way of introduction. Through much of the twentieth century, the most influential notion of "reduction" was a semantic notion, introduced by logical positivists such as Rudolf Carnap. A semantic reduction of A to B is essentially a (re-)definition of A in terms of B. In its deeper history, this notion of reduction can be seen as stemming from the early modern project of trying to make science more like mathematics, with a small core of primitive definitions and axioms (self-evident truths of reason for the rationalists, simple ideas for the empiricists) from which everything else could be derived on the model of mathematical construction and proof. The logical positivists initially linked semantic reduction with the Verification Theory of Meaning (the thesis that a term is defined in terms of its verification conditions), the primitives being either sense data or terms in an object-language. Later versions of the theory tended to emphasize bridge laws connecting the reduced science (say, chemistry or biology) with the reducing science (say, physics). Semantic reductionism made its way into philosophy of mind in the form of logical behaviorism and analytic functionalism, and was the target of the anti-naturalisms of Moore and Hare in ethics. With the exception of some remaining analytic functionalists, it is a view with relatively few contemporary advocates.

A second notion of "reduction" finds its locus classicus in Oppenheim and Putnam's (1958) "Unity of Science as a Working Hypothesis". This type of reduction, which Oppenheim and Putnam called a micro-reduction , is not semantic in character. Rather, it is a form of explanation in which the properties of a complex object can be "reduced", in the sense of "completely explained", in terms of the interactions of the object's proper parts. (Or at least of things whose level of complexity is at a lower level, leaving open the question of whether there can be externalist micro-reductions.) Whereas Carnap's semantic reductionism was a kind of a priori canon about the language of science, Oppenheim and Putnam saw the micro-reducibility of the special sciences to physics as a kind of second-order empirical hypothesis. They further differentiated two sub-classes of micro-reductions: smooth or conservative reductions, in which the terms and laws of the reduced domain are preserved and explained, and eliminative reductions, in which the mature reducing science eliminates the need for the theoretical postulates of the reduced science. (One might think of this as "reducing" the ontology, not so much in the sense of breaking it down into constituents as of decreasing the number of scientific kinds.)

Oppenheim and Putnam did not go far in discussing the modal status of micro-reductions. However, micro-reductions have often been taken to be metaphysically necessary . That is, if A is micro-reducible to B, then B → A is metaphysically necessary, and A is metaphysically supervenient upon B. Moreover, it is often assumed that, because such reductions are supposed to be explanations , the necessity ought to be epistemically transparent. (If one makes this assumption, then successful micro-reductions will take on some of the features of semantic reductions: if A is micro-reducible to B, then one should be able to reconstruct the properties of objects in domain B out of the objects and properties of domain A. This produces something like a definition, though not a definition of the use of A-terms in ordinary language. However, reductions that require contingent bridge laws do not meet this test.)

Not all advocates of micro-reduction have viewed it as merely a working hypothesis. In philosophy of mind, in particular, one often still hears micro-reductionism voiced in distinctively normative tones. That is, unless the mind can be reduced to what the brain does, some dire consequences (such as ontological elimination) are said to follow. (See discussion in Stich and Lawrence (1994).) In the 1980s, indeed, it was a kind of orthodoxy that there is a forced choice between reduction and elimination. (For the most part, people have stopped calling Oppenheim and Putnam's "eliminative reductions" reductions .) In the 1990s, philosophers of mind became more concerned that there are mental phenomena (consciousness, qualia, first-person perspective, intentionality, normativity of belief) that cannot be reductively explained in terms of brain states, giving rise to discussions of this "explanatory gap" (Levine 1983) and a growing advocacy of property dualism and non-reductive physicalism. By this time, however, the philosophers of science had largely decided that complete inter-level reductions were in fact pretty rare. (See Horst 2007 for a discussion of the implications of post-reductionist philosophy of science for conversations in philosophy of mind.)

Type-Identity as a Reductionism

In undergraduate textbooks and courses in philosophy of mind, a rather different thesis, popular in the 1960s, is often characterized as "(classic) reductionism". This is the type-identity thesis, which claims that mentalistic types (like PAIN) are identical with physical or neural types (like C-FIBER FIRING). While some of the seminal discussions of type-identity were couched in terms of an empirical-sounding hypothesis that the thesis would prove true, type-identity is at its core a metaphysical claim, and seems to have arisen within philosophy of mind, unlike semantic and micro-reduction, which had their origins in philosophy of science. Unlike micro-reduction, type-identity is a biconditional relation: if pains and C-fiber firings are type-identical, then X is a pain if and only if it is a C-fiber firing.

Type-identity, like logical behaviorism, is often covered in philosophy of mind courses as an unsuccessful view whose better insights were appropriated by functionalism. Indeed, functionalism is often touted as having vanquished type-identity theory, through pointing out that there are legitimate scientific kinds -- those that are functionally-defined -- that are multiply realizable . Human hearts are structurally different from earthworm hearts and artificial hearts, and are made of very different types of stuff from at least the latter, yet all are hearts by dint of having the function of pumping blood. Adder circuits in a present-day computer are made up of silicon microcircuits, whereas those of a previous generation were made up of vacuum tubes. But if this is so, then functional kinds are not type-identical with the things that realize them in particular objects or organisms. Being made like the adder circuit in my Mac may be a sufficient condition for being an adder circuit, but it is not a necessary condition. And with the rising popularity of a functionalist interpretation of psychological kinds in the 1970s, type-identity began to wane in popularity as an account of psycho-physical relations.

Because type-identity is sometimes called "reductionism", functionalism is often presented as an alternative to reductionism. Yet this is potentially misleading. On the one hand, analytic functionalists do view their analysis as a semantic reduction of mentalistic terms to a functional (though not a structural or physical) vocabulary. On the other hand, many functionalists assume that an analysis of the realizing system will provide a micro-explanation of the functional properties of the system. (Indeed, philosophers like Lewis approach psychological kinds by way of a functional analysis that then receives a micro-explanation.) When functionalism is opposed to reductionism, the real point of difference is with a metaphysical notion of "reduction" involving type-identity. The proponent of reduction-as-type-identity holds that the relation between the kind-terms in two domains of discourse is one-to-one; the functionalist holds that it is one-to-many -- or, as it is commonly expressed, that functional kinds are multiply realizable .

Here, the perceived strength of the functionalists' argument may depend on whether one is interested in metaphysics or philosophy of science. Some metaphysicians, such as Jaegwon Kim (1993 and essay in this volume), suggest that mental and (other) functional kinds may be reducible (type-identical) to a disjunction of the physical/structural kinds of the various physical systems that can realize them. Similarly, some philosophers have suggested that the various realizers of a functional property do provide type identities, but only local ones, relative to a particular type of system or organism. That is, pain may be type-identical with C-fiber firings in humans, with green goo flowing in Martians, and with a certain circuit state in androids. Philosophers more directly engaged with philosophy of science, or with the sciences themselves, tend to see this move as being out of step with how the kinds at a given level of organization are individuated.

More Recent Developments

In recent years, discussions of relations called "reduction" have increasingly drawn upon resources from outside the philosophy of mind. Several of the writers in this volume represent this trend of either exploring specific case studies in the cognitive and biological sciences, or drawing upon more general critiques of semantic reduction, micro-reduction and type-identity that have been offered in philosophy of science.

In short, the situation might be summed up as follows: in the heyday of reductionism (say, the mid-twentieth century), 'reduction' tended to mean either semantic reduction, type-identity, or a very strong sort of micro-reduction capable of showing that the properties of the reduced system are all necessary consequences of the reducing system. But all of these notions have encountered serious philosophical problems, some purely analytic, others drawn from the observation that such relations are not generally found in the sciences, even in supposed paradigm cases of reduction. (See summary in Silberstein 2002.) At the same time, there is certainly something right about reductionism. No one would deny that micro-explanation of some sort is an important and powerful explanatory strategy, nor that there is some strong relation between realized and realizing systems. And these relations, whatever they might be in detail, are often called "reductions" by the scientists. What, then, should we say? That "reductionism" is dead and that we ought to find another terminology (say, "mechanistic explanation") for the things scientists call "reductions"? Or that examination of case studies has revealed a number of genuine reductions, but also that previous generations of philosophers have misunderstood the nature of reduction? Or might it be that the standard critiques of various notions of "reduction" do not really have the force that they are commonly supposed to have?

Hands-On Philosophy of Science

The first three essays in the collection represent what I would call "hands-on philosophy of science", in which engagement with the particulars of scientific research plays a substantial role in guiding philosophical interpretation of those sciences.

Valerie Hardcastle and Rosalyn Stewart (Ch. 1) argue that research in the cognitive sciences is sometimes hampered by an assumption that the goal is to reduce mind to brain, and draw upon case studies that provide evidence that more broadly somatic states are also needed to explain conditions such as depression. Their article provides both scientists and philosophers with reasonable cautions about the dangers of too-readily assuming a neuro-reductionist strategy. Lamentably, it is the only entry in the volume from any form of the embodied-cognition camp, which has arguably offered some of the more empirically-grounded considerations of alternatives to reductive approaches. While I am not myself a practitioner of bodily approaches to cognition, I am glad that at least this one representative of that school found its way into this collection.

John Bickle (Ch. 2) and Peter Godfrey-Smith (Ch. 3) each take the view that a philosophical notion of "reduction" should principally be guided by careful study of the actual sciences of cognition, rather than by philosophers pursuing their projects in pre-decided philosophical terms. The classic reductionisms of Carnap (1929) and Nagel (1961) may be seen as object lessons here -- little if anything can be "reduced" in the ways they supposed. But the moral Godfrey-Smith and Bickle draw is not that reductionism has been refuted, but that philosophers have failed to understand what takes place in real scientific reductions. Or, to put it differently, the word 'reduction' gets used in a lot of ways by scientists and philosophers, and the most important thing to do is not to wrangle over who gets dibs on the word, but to understand the legitimate forms of explanation at work, however one might prefer to label them. With this I am at least halfway in agreement. Philosophers of cognitive science should attend carefully to real science in the form of case studies (or even participation in empirical research); part of our job there is to clarify the nature(s) of the type(s) of explanation at work in different strands of research. On the other hand, when the history of a word is fraught with a significant history, and in this case a history whose reach has extended outside of academia into the popular press, there are also rhetorical considerations to be taken into account that go beyond mere wrangling over words. In particular, the word 'reduction' has a long history of association with views that have been seen as threatening to our humanistic self-image as beings with important traits such as free will, consciousness, and intrinsic worth and dignity. To the extent that there is a large audience, both within the academy and outside it, who are likely to hear claims for something called "reductionism" against this background, my own view is that it is more in accordance with my duties as a public intellectual to find alternative ways to label the forms of explanation I find doing important work in the sciences. Apart from that rhetorical choice, I find Godfrey-Smith's emphasis on mechanisms and models quite agreeable and right-headed.

Bickle's views present in some ways a more radical challenge. His account of what ought to be counted as a "reduction" emphasizes the role of causal interventions in low-level mechanisms and tracking the effects of these across levels. Bickle's characteristically meticulous attention to scientific detail may make for hard reading for the reader who is not literate in the appropriate sciences. But his explanations, in which sub-cellular activities play a crucial role, are striking in their contrast to prevailing assumptions that the "neural correlates" for mental states would generally be something on the order of anatomical areas that "light up" in an fMRI scan. Philosophers interested in things called "reduction" have often assumed that mental phenomena could be reduced to sub-cellular (and ultimately physical) phenomena by way of several intermediate reductions across intermediate levels of complexity . Bickle suggests that often we can dispense with all that, and reduce psychological phenomena directly to low-level neural (or perhaps even biochemical) phenomena.

Reductive Explanation and Reductive Metaphysics?

While Bickle (2003) has decided to abandon traditional metaphysical projects altogether, the majority of philosophers interested in reductionism are probably still interested in metaphysical issues like supervenience, and in how they relate to whatever notions of "reduction" seem most promising in the sciences. The remainder of the essays in the volume are devoted either to exclusively metaphysical issues, or to the relations between metaphysics and reductive forms of explanation. (It would have been very interesting to see more discussion of whether more recent formulations of "reductionistic" claims like those offered by Bickle and Godfrey-Smith have the same sorts of necessitarian metaphysical implications as older notions. But this is not so much a fault of the volume as a symptom of the fact that the philosophies of science and of mind seem at risk of dividing into camps that are interested in metaphysical issues and camps interested in hands-on case studies.)

Jaegwon Kim (Ch. 5) argues that only functional reductions can provide both metaphysical reduction and reductive explanation. Reductions by way of identity do secure metaphysical reduction but not reductive explanation, and reductions involving bridge laws do neither. Peter Lipton (Ch. 6) agrees that there can be reductive explanations without type-identity.

Ceteris Paribus Laws, Disjunctive Properties, and the Special Sciences

The Functionalist doctrine that mentalistic kinds are multiply realizable has spawned a number of debates within philosophy of psychology, debates which also have wider implications for the relation of the special sciences to fundamental physics. If there are laws within a special science -- say, psychology -- and its kinds are multiply realizable, it is not only the kinds of the special sciences, but also their laws that are, in some sense, irreducible. There is not a one-to-one correspondence between psychological laws and the physical laws governing their underlying mechanisms, because different sets of physical laws will be at work in the different types of realizing systems. And by the same token, the psychological law cannot be re-constructed from the vocabulary used in describing any of its realizing systems. Even micro-reduction might seem compromised, insofar as multiple realization entails that there is not a single micro-reduction for a psychological law.

Reductionists, however, have suggested two (alternative and incompatible) solutions to this problem. The first is to treat the disjunction of the realizing systems as collectively providing a reduction base for the laws and kinds of the special sciences. The second is to hold that there is not a single reduction for the multiply-realizable kinds, but there are nonetheless more "local" reductions to be had for each individual type of realizing system. (A third possibility, of course, is to insist that the absence of a single, ontologically-tidy reduction base implies that the special sciences are ontologically suspect.)

Historically, this problem has often been linked with other issues about laws in the special sciences: particularly, with the claim that the special sciences have only ceteris paribus laws while fundamental physics (or perhaps all of physics and chemistry) can lay claim to strict and universal laws. Indeed, multiple realization is often cited as the explanation both for the nomicity of special-science laws and for their exceptions. However, there has been a long-standing and lively debate about the status of the special sciences and their laws, concerning whether ceteris paribus laws are good enough to justify the honorific "science", and whether the special sciences are "autonomous" or require further grounding in fundamental physics in order for their laws to be seen as legitimate or warranted.

Peter Lipton (Ch. 6) re-examines questions about the relation between ceteris paribus macro laws and the strict laws in physics thought to underlie them. He argues that ceteris paribus laws can have explanatory force regardless of whether they are reducible to strict lower-level laws, echoing a theme going back to Fodor (1974), and that macro laws sometimes are better at capturing the causes correctly. More important, to my mind, is his recognition that "fundamental" laws are not truly exceptionless either. I tend to view this as bringing into question the whole received problematic about "strict" and "ceteris paribus" laws as based in a confusion. (Compare Cartwright 1983, Horst forthcoming.) But Lipton's focus is more on the relationship between macro laws and micro laws, and particularly with the status of the former.

David Papineau (Ch. 7) argues that physicalism (understood as the view that the universe is causally closed under physics) does not entail microphysicalism (the view that the universe is causally closed under the physics of the most basic units of matter). Put differently, one can embrace a physicalism that admits irreducible broad laws, and even properties of complex systems that do not supervene upon the intrinsic properties of their microphysical parts. Papineau seems most concerned with problems about classical events supervening upon quantum events; however, this article provides useful considerations for anyone interested in supporting a non-reductive physicalism or an emergentism consistent with physicalism. Nonetheless, non-physicalists may be left seeing it as supplying only a proof of the consistency of physicalism with non-reductionism, and wondering what reasons are left to prefer physicalism once the reductionist ladder has been kicked away.

Barry Loewer (Ch. 8) also takes up the question of ceteris paribus laws in the special sciences. Unlike Papineau, Loewer embraces microphysicalism, and concludes that, if there are metaphysically independent laws for the special sciences, these overdetermine their effects. The second contribution of his paper is a suggestion about how non-fundamental laws in the special sciences might get their lawlike character: namely, from fundamental dynamics combined with constraints on the initial conditions of the universe. Such an explanation has long been offered in the case of the temporally asymmetric nature of entropy, but this is the first time I have seen it offered as a more general thesis about emergent or resultant properties, and I regard it as an important proposal, as it extends an analysis that proved useful in one area in a way that should be possible to test. Working it out in detail for all of the particular laws in the biological and social sciences would, of course, require a much longer treatment, and this reader is somewhat skeptical that all would yield to this analysis.

Louise Antony (Ch. 9) addresses issues raised by Jaegwon Kim concerning the suitability of disjunctive properties consisting of the various realizers of higher-level kinds to count as nomic. She stresses the importance of distinguishing disjunctive predicates from the properties they express. While disjunctive predicates are not projectable, if they are the class of realizers of a higher-order predicate, they are necessarily co-extensive with that higher-order predicate, and so pick out the same properties. Hence, if the higher-level predicate picks out a nomic property, the disjunction of lower-level predicates must do so as well.

Causal Exclusion

Another familiar problem in philosophy of mind is that of causal exclusion. If mental events are token-identical with physical events, then mental and physical descriptions pick out numerically identical causes. Semantic reduction, type-identity, and micro-reduction all imply token physicalism, and so they can all avail themselves of this principle. But if one rejects these forms of reductionism, and holds that mental properties are distinct from physical properties, a puzzle arises. An event with a mental cause -- say, an intentional action -- also presumably has physical causes. Indeed, if one embraces the principle that physics is causally closed (i.e., that every physical effect has an adequate physical cause), there seems to be no work left for the mental cause to do. This puzzling result can be made even more problematic if one endorses the causal exclusion principle : namely, that there cannot be more than one sufficient cause for an effect. There are several possible solutions to the puzzle: (1) treat mental events as epiphenomenal (i.e., as having no causal powers, at least on the physical world), (2) re-affirm some type of psycho-physical reduction, (3) deny causal closure, or (4) deny the exclusion principle.

Peter Menzies (Ch. 11) argues that non-reductive physicalists need not be troubled by the causal exclusion problem if that is interpreted according to a difference-making account of causation. When a mental property is the difference-maker for a behavioral property, a physical property may be causally sufficient to produce the behavioral property as well, yet fail to be a difference-maker for it.

James Woodward (Ch. 12) urges that philosophers have argued for the causal inertness of the mental on the basis of a mistaken analysis of causation (that a cause is simply anything nomologically sufficient for its effect) combined with the D-N analysis of explanation. Woodward suggests that we replace these with an interventionist account of causation and causal explanation. Significantly, an interventionist understanding of causation allows for macroscopic causal explanations, particularly in such cases as those in which manipulation of variables of multiply-realizable mental states can be used to predict commonalities of outcome. Moreover, on the interventionist analysis, we should reject the causal exclusion principle, as there can be multiple types of interventions that reliably produce characteristic changes in outcome.

Daniel Stoljar (Ch. 13) argues that the causal exclusion principle is more persuasive as an argument against dualism than against non-reductive physicalism. The basis of the difference is that, in the case of dualism, the irreducible properties are (putatively) strongly modally distinct, whereas in the case of non-reductive physicalism, they are only numerically or weakly modally distinct, and in the case of numerical and weakly-modal distinctness, there are clear counter-examples to the exclusion principle, such as cases where the causal sufficiency of a determinate property does not exclude the causal relevance of its determinable property. Karen Bennett (Ch. 14) argues to much the same conclusion: that only physicalists can escape the exclusion principle, and that they can do so because they mean something weaker than what dualists mean in claiming that mental properties are "distinct" from physical properties.

These entries represent sophisticated attempts to solve the causal exclusion problem, and draw upon contemporary resources in philosophy of science to shed light on problems in metaphysics of mind. However, I have never gotten particularly excited about this particular problem, as I find little reason to endorse two of the assumptions of the tetralemma from which it arises. On the one hand, where do we get this principle that an event cannot have two sufficient causes? It strikes me as a kind if metaphysical apriorism that is in tension with what one finds in the sciences themselves. (In biology and neuroscience, after all, causal redundancy is seen as a virtue.) On the other hand, where do we get the principle of causal closure? It is not entailed by any first-order scientific theory I am aware of. Rather, it seems to be either an independent philosophical commitment or else a methodological maxim (" treat an experimental situation as though it were a closed system", or perhaps " look for sufficient physical causes") masquerading as an empirical discovery.

Given the continuing influence of notions of "reduction" in philosophy of mind, this book provides a welcome compilation of the current state of debates about both explanation and metaphysics. It should prove a useful textbook for graduate and advanced undergraduate courses, as well as providing professionals with some contemporary touchstones. It is probably not suitable as a stand-alone introduction to debates about reduction, as most of the articles are responding to a number of decades-old debates within philosophy of mind and philosophy of science. But it is not clear that adding a half-dozen classic articles would have improved the book, as the common points of reference are part of the "received canon" and readily available in any of a number of standard textbooks.

The editors are to be commended for including articles representing what I have called "hands-on" philosophy of science along with the more metaphysical articles. If there is a way in which the volume leaves me disappointed, it is the fact that the book does not bring these two strands of contemporary philosophy of science and mind into closer contact. The articles by Bickle and Godfrey-Smith, for example, reflect the attitude that I find prominent among philosophers of science -- that "classic" forms of reduction of the sort found from Carnap to Nagel are dead. One is left wanting to know whether the weaker forms of "reduction" they explore can support the same sorts of metaphysical conclusions that were associated with older types of reduction.

Conversely, it would be interesting to re-assess the main lines of metaphysical dispute, such as multiple realization, causal exclusion, and the status of the special sciences, in light of the results of the kinds of analysis of actual explanation in the special sciences offered by Bickle and Godfrey-Smith. Some new-school philosophers of science (including Bickle in his 2003 book) take the view that we should simply abandon the questions of traditional analytic metaphysics in order to devote our attention to the sciences themselves. I, for one, tend to side with the new school's rejection of many of the canons of Empiricist philosophy of science that seem to have found a last stronghold in philosophy of mind, but am not convinced that this means that we need abandon metaphysics entirely. We are in need of a discussion of the implications of contemporary philosophy of science for the metaphysics of mind. Perhaps this volume will help to provide the pieces from which such a discussion can proceed.

Bickle, John. 1998. Psychoneural Reduction: The New Wave . Cambridge, MA: MIT Press.

---. 2003. Philosophy and Neuroscience: A Ruthlessly Reductive Account . Kluwer.

Carnap, Rudolf. 1929. Der Logische Aufbau der Welt . Leipzig: Felix Meiner Verlag.

Cartwright, Nancy. 1983. How the Laws of Physics Lie . Oxford University Press.

Fodor, Jerry. 1974. Special Sciences (or: the distunity of science as a working hypothesis). Synthese 28:97-115.

Horst, Steven. 2007. Beyond Reduction: Philosophy of Mind and Post-Reductionist Philosophy of Science . New York: Oxford University Press.

---. Forthcoming. Laws, Mind and Freedom.

Kim, Jaegwon. 1993. Supervenience and Mind: Selected Philosophical Essays . Cambridge: Cambridge University Press.

Levine, Joseph. 1983. Materialism and Qualia: The Explanatory Gap. Pacific Philosophical Quarterly 64:354-61.

Nagel, Ernest. 1961. The Structure of Science . New York: Harcourt, Brace and World.

Oppenheim, Paul, and Hilary Putnam. 1958. Unity of Science as a Working Hypothesis. In Concepts, Theories, and the Mind-Body Problem , edited by H. Feigl, M. Scriven and G. Maxwell. Minneapolis: University of Minnesota Press.

Silberstein, Michael. 2002. Reduction, Emergence and Explanation. In The Blackwell Guide to the Philosophy of Science , edited by P. Machamer and M. Silberstein. Malden, MA and Oxford: Blackwell.

Stich, Stephen P., and Stephen Laurence. 1994. Intentionality and Naturalism. In Midwest Studies in Philosophy , edited by P. A. French, T. E. Uehling, Jr. and H. K. Wettstein. Notre Dame, IN: University of Notre Dame Press.

Drive-Reduction Theory of Motivation In Psychology

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

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Saul McLeod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

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Drive reduction thosry is a theory of learning in which the goal of motivated behavior is a reduction of a drive state. The theory assumes that all motivated behavior arises from drives, stemming from a disruption in homeostasis, and that responses that lead to reduction of those drives tend to be reinforced or strengthened.

For example, hunger creates a drive to eat. Actions that reduce the tension or satisfy the need are reinforced, making it more likely that the individual will engage in the behavior again when faced with the same need or tension in the future.

What is the main idea of drive theory?

Drive-reduction theory is based on the idea that the primary motivation behind all human behavior is to reduce ‘drives.’

A ‘drive’ is a state of arousal or discomfort that is triggered by a person’s physiological or biological needs, such as hunger, thirst, and the need for warmth.

According to the theory, when a person’s drive emerges, they will be in an unpleasant state of tension which causes them to behave in such a way that this tension is reduced.

To reduce the tension they feel, they will seek out ways to satisfy their biological needs.

Drive-reduction theory is based on the concept of homeostasis, which is the idea that the body actively works to maintain a state of balance or equilibrium.

According to the theory, as soon as there is an unmet need within the body, a person starts behaving in a manner that allows them to address this need, reduce the drive, and achieve a state of balance.

Who developed the drive-reduction theory?

Drive-reduction theory was created by behaviorist Clark Hull and was developed further by his collaborator Kenneth Spence.

Hull based his theory on the earlier theories that relate to the concepts of motivation, taking inspiration from prominent scientists such as John B. Watson, Ivan Pavlov , and Edward Thorndike.

Hull’s theory became popular during the 1940s and 1950 as a way to explain behavior, learning, and motivation.

Hull based his theory on the concept of homeostasis, which is the idea that all organisms seek to keep their internal physiologic systems stable and balanced.

Drive reduction theory proposes that the goal of motivated behavior is to reduce physiological arousal and return to homeostasis.

A drive is any internal factor that compels an organism to seek out certain stimuli or perform certain behaviors to reduce arousal.

According to drive reduction theory, all motivated behavior arises from drives, basically needs or wants stemming from a disruption in homeostasis (a state of equilibrium). The higher the level of arousal, the greater the drive (Hull, 1952).

Hull’s student, Kenneth Spence, also contributed greatly to Drive Reduction Theory. Spence disagreed with Hull’s assumption that performance improvement comes only due to habit factors and emphasized the role of motivation.

He also believed that reinforcement can serve as a motivator for learning but that it does not necessarily enhance the learning of a response. This idea was later known as the Hull-Spence hypothesis of conditioning and learning (Spence & Spence, 1966).

Additionally, Spence posited that learning does not always occur by what has been learned, which he explained through latent learning. This is when an organism learns something but does not display the behavior until there is a reason or incentive.

For example, a rat in a maze might initially explore randomly, but after being rewarded for finding the exit, it will display the learned behavior of going straight to the exit (Spence & Spence, 1966).

This concept of latent learning is an important one because it helps to explain why organisms do not always perform according to what they have learned. It also provides evidence for the role of motivation in learning.

While drive-reduction theory was once a dominant theory in psychology, it is largely ignored today with the development of newer theories.

Although it is no longer a widely accepted theory, it is still useful to understand how earlier researchers sought to explain human motivation.

How does drive-reduction theory explain human behavior?

Drive-reduction theory suggests that human behavior results from wanting to reduce the drives we have. It is thought that there are primary and secondary drives.

Primary drives are innate biological needs such as being hungry or thirsty. Whereas secondary drives are those learned through conditioning or association with a primary drive, such as money and social acceptance.

To minimize the discomfort that is being caused by primary drives such as hunger, someone may go to the shop, purchase food, cook it, and then eat it.

The drives cause all these behaviors, according to drive-reduction theory. After the individual’s needs are fulfilled, they reach homeostasis once again, and the drive to fulfill their needs is reduced.

What is behaviorism?

Behaviorism, also known as behavioral psychology, is the belief that environmental stimuli shape human actions.

Drive-reduction theory is founded on behaviorist principles to explain behavior. The key concepts of behaviorism include arousal, homeostasis, conditioning, and reinforcement.

Arousal in psychology is a state of physiological activation or a cortical response associated with sensory stimulation. Behaviorists believe that we are motivated by arousal.

As arousal levels change, we are said to naturally change our behavior to get back to our ‘optimal’ level of arousal.

If arousal is too low, then we may do something to stimulate ourselves. Whereas, if arousal is too high, we may try to reduce stimulation by relaxing or choosing to be alone.

Homeostasis

Homeostasis is a term that refers to the physiological balance which is achieved when an organism’s internal needs have been met.

An organism will regulate its internal environment to achieve this balance, such as by adjusting body temperature and blood sugar levels or achieving hydration.

In psychology, homeostasis can also refer to keeping your mental state balanced.

Conditioning and reinforcement

Conditioning means learning about the world through reinforcement. Hull explained human behavior in terms of conditioning  and reinforcement .

According to drive reduction theory, conditioned responses are reinforced or strengthened because they contribute to drive reduction.

In drive-reduction theory, the reduction of the drive functions as a reinforcement of the behavior that helped the person satisfy their unfulfilled need.

According to the theory, such reinforcement increases the likelihood that the person will behave in the same manner in the future to address that particular drive.

Stimuli associated with reducing arousal become associated with pleasure and act as reinforcers. For example, if someone has a very high urge to eat when hungry, they might eat a snack to satisfy their appetite and reduce their hunger drive.

Eventually, that person may begin to associate the feeling of eating a snack (the experience of drive reduction) with the stimulus that induces that behavior (the sight or smell of snacks), which leads to reward-driven learning and strengthens the association between those stimuli (Hull, 1952).

Drive-reduction theory, therefore, works on the same stimulus-response relationship that is associated with the conditioning form of learning.

Mathematical Model

Hull created a mathematical ‘formula’ to explain his theory of human behavior, which is as follows:

sEr = V x D x K x J x sHr – sIr – Ir – sOr – sLr

sEr: Excitatory potential, or the likelihood that an organism will produce a response (r) to a stimulus (s).

V: Stimulus intensity dynamism, meaning some stimuli will have greater influence than others.

D: Drive strength, determined by the amount of biological deprivation.

K: Incentive motivation, or the size or magnitude of the goal.

J: The delay before the organism is allowed to seek reinforcement.

sHr: Habit strength, established by the amount of previous conditioning.

sIr: Conditioned inhibition caused by previous lack of reinforcement.

Ir: Reactive inhibition or fatigue.

sOr: Random error.

sLr: Reaction threshold, or the smallest amount of reinforcement that will produce learning.

Hull was criticized for having an overly complex formula. It may be easier to consider the drive-reduction theory in 2 simpler parts:

Internal stimulus + response = drive reduction

Drive reduction = repetition

Critical evaluation of drive-reduction theory

While drive-reduction theory was well-received in the 1940s and 1950s as an explanation for motivation, it is not as popular now.

Drive reduction theory has been criticized for its lack of empirical support and its biologically deterministic view of behavior. Contemporary scholars initially viewed Hull’s mathematical approach as overly complex and unable to explain human motivation fully.

The 1970s mostly abandoned Hull’s theory, as it could not explain many complex human behaviors, such as aggression, altruism, and cognitive processes. In addition, it could not account for the role of motivation in learning  (Mills, 1978) .

As soon as the 1950s, researchers realized that Hull’s equation did not always provide valid results, even if altered. Researchers eventually concluded that no simple system could be responsible for the complexity of the behaviors of animals and humans (Mills, 1978).

It has been criticized for not being generalizable and for being unable to account for behaviors that do not reduce drive. Some main criticisms of drive-reduction theory include the following:

It ignores the role of secondary reinforcers

Drive reduction theory has also been criticized for its emphasis on basic needs over higher-level ones. Practically, this means that individuals with different basic needs may differ in their motivations to engage in certain behaviors.

For example, an athlete might be motivated by the need for relaxation and may find running to be intrinsically rewarding, while another individual might be motivated by the need for social interaction and may instead find going to the gym to be intrinsically rewarding  (Mills, 1978) .

The issue with Hull’s theory is that it fails to explain how drive can also be reinforced by secondary drives.

For instance, money and social acceptance are secondary drives that are not needed to fulfill our primary biological needs, but money can be used to buy food to survive on and meet our primary needs.

Why do we overindulge?

Drive-reduction theory does not explain why we may overindulge in our primary needs even when they are fulfilled.

For instance, eating a three-course meal having another slice of pizza when already full, or continuing to drink when not particularly thirsty.

What about thrill-seeking behaviors?

Drive-reduction theory has been criticized for not explaining why humans engage in thrill-seeking behaviors.

For example, someone may leave the comfort of their home to go hike up a mountain or bungee jump.

These behaviors go against drive-reduction theory’s general ideas, as people will purposely seek out behaviors that will take them away from meeting their biological needs or make them uncomfortable.

Other behaviors that cannot fully be explained by drive-reduction theory and can be explained by other factors include:

Watching scary movies where people purposely make themselves uncomfortable.

Camping which takes someone away from their comfortable home.

Fasting behaviors where someone will purposely not fulfill their primary need.

Extreme workouts which are purposely uncomfortable.

Being aroused is not always positive

Drive-reduction theory is unable to explain why humans fail under high arousal. While excitement or feeling nervous can help someone, there is a point where the anxiety becomes too much and actually prevents someone from performing to a high standard.

For instance, someone may become so anxious about completing an examination that they falter under pressure and do not perform as well as they could do.

Drive Reduction vs. Drive-induction Theory

Drive induction theory is another approach to understanding motivation that is often considered as an alternative or response to drive reduction theory.

Unlike Hull’s theory, drive-induction theory does not assume that all behaviors are motivated by the need to reduce a physiological state of arousal. Instead, it suggests that the innate need for novelty and challenge may drive some behaviors.

For example, an individual might engage in risky or challenging activities like mountain climbing because they find it intrinsically rewarding, regardless of whether or not they experience arousal reduction following these activities.

Drive reduction and drive induction theories provide valuable insights into how motivation influences behavior; however, they take different approaches to explain this phenomenon.

How has drive-reduction theory impacted our idea of motivation?

Despite its limitations, drive reduction theory was an important contribution to understanding behavior. It helped to establish the role of conditioning in learning and provided evidence for the importance of motivation in determining behavior.

Additionally, Hull’s mathematical approach laid the foundation for subsequent research on reinforcement theory.

While it is not favored in psychology today, drive-reduction theory still influenced other psychologists at the time and helped to contribute to later research.

In general, drive reduction theory provides an important framework for understanding how biological needs influence behavior, especially regarding hunger and tiredness. It highlights rewards and deprivation’s role in motivating behavior and shows how motivation can affect our performance and overall well-being.

Say that someone eats very little for breakfast and then decides to go for a run.  This person’s body will be experiencing a “deprivation of drive,” or a lower level of hunger, which in turn increases their motivation to exercise and may also increase their performance while they are running.

Alternatively, if someone eats a large breakfast and then sits down to watch TV all day, they will experience less hunger due to the positive reward (of watching TV) that reduces their motivation for engaging in physical activity.

The drive reduction theory could also explain why people feel tired or lethargic after a long day at work. For example, if someone has been working hard and gets little to no positive reinforcement throughout the day (such as praise or recognition), they will likely experience a feeling of exhaustion, which in turn lowers their motivation to keep going.

Alternatively, if someone is given frequent breaks during their busy day and feels valued by their boss, they are more likely to find the energy needed to continue working effectively.

Many motivational theories that emerged during the 1950s and 1960s were either based on Hull’s original theory or were focused on providing alternatives to drive-reduction theory.

An example of another motivation theory that emerged as an alternative to drive-reduction theory is Abraham Maslow’s hierarchy of needs.

Maslow’s famous hierarchy explains that while humans are motivated to meet their basic physiological needs, they are also motivated to meet their psychological needs of love, belonging, and self-esteem.

Once these have been achieved, the theory states that humans then strive to reach the self-fulfillment needs of self-actualization .

Maslow’s theory of motivation thus expands on drive-reduction theory to explain why humans are motivated past their basic needs.

A study from 1956 found that while drive reduction does indeed play a role in motivation, rewards seemed to do more than reduce drives and that incentives have a similar effect to drive reduction (Seward, 1956).

This research paved the way for incentive theory which states that sometimes humans are motivated to do things because of rewards.

How do we form habits according to DRT?

Incentives or rewards can play a big role when creating a habit or behavior. If the reward is instantly given after an action is performed and is repeatedly given in a consistent manner, this will result in the development of a habit.

How does DRT relate to sports?

Drive-reduction theory suggests that the more an athlete is aroused, the better their performance will be.

This means that a very high arousal level would result in a higher performance. However, this only applies when the athlete is highly skilled in their sport.

Experienced athletes tend to perform better under pressure due to their superior skills. If the athletic skill of an athlete is not well-learned, performance is likely to deteriorate under pressure.

Often, a beginner’s skill level decreases if they are completing a sport using new skills. This does, however explain why experienced athletes perform better under pressure. A beginner’s skill level often

How can DRT be applied to education?

The principles of drive-reduction theory could be applied to education if one considers the need to satisfy curiosity as the drive needed to motivate learners.

Hull reduced the art of learning to mere habit formation and its reinforcement. The theory attached sufficient importance to the needs, drives, incentives, reinforcement, and adequate motivation for achieving satisfactory results in the process of teaching and learning.

How does DRT explain eating behavior?

According to drive-reduction theory, organisms seek food when they experience the drive of hunger.

Any behavior that reduces the drive is likely to be repeated by both humans and animals, so this is why they continue to eat.

The reduction of the drive by eating serves as a positive reinforcement (i.e., a reward) for the behavior that caused such drive reduction.

Hull, C. L. (1943). Principles of behavior: An introduction to behavior theory . New York: Appleton-Century-Crofts.

Hull, C. L. (1952). A behavior system; an introduction to behavior theory concerning the individual organism .

Pavlov, I. P. (1897). The work of the digestive glands . London: Griffin.

Mills, J. A. (1978). Hull’s theory of learning: II. A criticism of the theory and its relationship to the history of psychological thought .

Montgomery, K. C. (1954). The role of the exploratory drive in learning. Journal of Comparative and Physiological Psychology , 47 (1), 60.

Seward, J. P. (1956). Drive, incentive, and reinforcement. Psychological Review, 63 (3), 195.

Spence, J. T., & Spence, K. W. (1966). The motivational components of manifest anxiety: Drive and drive stimuli. Anxiety and behavior , 291326 .

Watson, J. B. (1913). Psychology as the behaviorist views it . Psychological Review, 20 , 158-178.

Watson, J. B. (1930). Behaviorism (revised edition). University of Chicago Press.

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What Is Hypothesis Testing?

• How It Works

4 Step Process

The bottom line.

• Fundamental Analysis

Hypothesis Testing: 4 Steps and Example

Hypothesis testing, sometimes called significance testing, is an act in statistics whereby an analyst tests an assumption regarding a population parameter. The methodology employed by the analyst depends on the nature of the data used and the reason for the analysis.

Hypothesis testing is used to assess the plausibility of a hypothesis by using sample data. Such data may come from a larger population or a data-generating process. The word "population" will be used for both of these cases in the following descriptions.

Key Takeaways

• Hypothesis testing is used to assess the plausibility of a hypothesis by using sample data.
• The test provides evidence concerning the plausibility of the hypothesis, given the data.
• Statistical analysts test a hypothesis by measuring and examining a random sample of the population being analyzed.
• The four steps of hypothesis testing include stating the hypotheses, formulating an analysis plan, analyzing the sample data, and analyzing the result.

How Hypothesis Testing Works

In hypothesis testing, an  analyst  tests a statistical sample, intending to provide evidence on the plausibility of the null hypothesis. Statistical analysts measure and examine a random sample of the population being analyzed. All analysts use a random population sample to test two different hypotheses: the null hypothesis and the alternative hypothesis.

The null hypothesis is usually a hypothesis of equality between population parameters; e.g., a null hypothesis may state that the population mean return is equal to zero. The alternative hypothesis is effectively the opposite of a null hypothesis. Thus, they are mutually exclusive , and only one can be true. However, one of the two hypotheses will always be true.

The null hypothesis is a statement about a population parameter, such as the population mean, that is assumed to be true.

• State the hypotheses.
• Formulate an analysis plan, which outlines how the data will be evaluated.
• Carry out the plan and analyze the sample data.
• Analyze the results and either reject the null hypothesis, or state that the null hypothesis is plausible, given the data.

Example of Hypothesis Testing

If an individual wants to test that a penny has exactly a 50% chance of landing on heads, the null hypothesis would be that 50% is correct, and the alternative hypothesis would be that 50% is not correct. Mathematically, the null hypothesis is represented as Ho: P = 0.5. The alternative hypothesis is shown as "Ha" and is identical to the null hypothesis, except with the equal sign struck-through, meaning that it does not equal 50%.

A random sample of 100 coin flips is taken, and the null hypothesis is tested. If it is found that the 100 coin flips were distributed as 40 heads and 60 tails, the analyst would assume that a penny does not have a 50% chance of landing on heads and would reject the null hypothesis and accept the alternative hypothesis.

If there were 48 heads and 52 tails, then it is plausible that the coin could be fair and still produce such a result. In cases such as this where the null hypothesis is "accepted," the analyst states that the difference between the expected results (50 heads and 50 tails) and the observed results (48 heads and 52 tails) is "explainable by chance alone."

When Did Hypothesis Testing Begin?

Some statisticians attribute the first hypothesis tests to satirical writer John Arbuthnot in 1710, who studied male and female births in England after observing that in nearly every year, male births exceeded female births by a slight proportion. Arbuthnot calculated that the probability of this happening by chance was small, and therefore it was due to “divine providence.”

What are the Benefits of Hypothesis Testing?

Hypothesis testing helps assess the accuracy of new ideas or theories by testing them against data. This allows researchers to determine whether the evidence supports their hypothesis, helping to avoid false claims and conclusions. Hypothesis testing also provides a framework for decision-making based on data rather than personal opinions or biases. By relying on statistical analysis, hypothesis testing helps to reduce the effects of chance and confounding variables, providing a robust framework for making informed conclusions.

What are the Limitations of Hypothesis Testing?

Hypothesis testing relies exclusively on data and doesn’t provide a comprehensive understanding of the subject being studied. Additionally, the accuracy of the results depends on the quality of the available data and the statistical methods used. Inaccurate data or inappropriate hypothesis formulation may lead to incorrect conclusions or failed tests. Hypothesis testing can also lead to errors, such as analysts either accepting or rejecting a null hypothesis when they shouldn’t have. These errors may result in false conclusions or missed opportunities to identify significant patterns or relationships in the data.

Hypothesis testing refers to a statistical process that helps researchers determine the reliability of a study. By using a well-formulated hypothesis and set of statistical tests, individuals or businesses can make inferences about the population that they are studying and draw conclusions based on the data presented. All hypothesis testing methods have the same four-step process, which includes stating the hypotheses, formulating an analysis plan, analyzing the sample data, and analyzing the result.

Sage. " Introduction to Hypothesis Testing ," Page 4.

Elder Research. " Who Invented the Null Hypothesis? "

Formplus. " Hypothesis Testing: Definition, Uses, Limitations and Examples ."

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Definition and reduction.

Published online by Cambridge University Press:  14 March 2022

While I do not accept any current analysis of theoretical terms I also reject certain criticisms of them. Specifically, I reject the criticism that the paradoxes of material implication and the counterfactual problem eliminate the explicit definition view; and I also reject the criticism that explicitly defined theoretical terms do not refer to anything which “really exists” or do not have “excess meaning.” I do argue, however, that the explicit definition view confuses and conflates the concepts of criterion and meaning analysis. I also defend reduction sentences against the counterfactual difficulty, but show, too, how this view is already logically committed to the network or postulational view of meaning. Finally, I show how the concept of reduction sentences confuses in several ways the concepts of criterion and meaning analysis—although not in quite the same way as explicit definitions do.

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Drive Reduction Theory and Human Behavior

Verywell / Hilary Allison 

Conditioning and Reinforcement

• Mathematical Theory of Behavior
• Alternatives

Drive reduction theory suggests that behavior is motivated by the need to reduce physiological imbalances or 'drives.' It is based on the idea of homeostasis, or the need to maintain a steady state. When people experience drives such as thirst or hunger, they are motivated to take actions that will restore the balance and return them to a state of equilibrium.

The drive reduction theory of motivation became popular during the 1940s and 1950s as a way to explain behavior, learning, and motivation. The theory was created by behaviorist Clark Hull and further developed by his collaborator Kenneth Spence. According to the theory, the reduction of drives is the primary force behind motivation .

While the drive reduction theory of motivation was once a dominant force in psychology, it is largely ignored today. Despite this, it's worthwhile for students to learn more about Hull’s ideas to understand his work's effect and see how other theorists responded by proposing their own theories.

This article explores how drive reduction theory works, criticisms of Hull's theory, and a few alternative motivational theories that have been proposed.

Overview of Drive Reduction Theory

Hull was one of the first theorists to attempt to create a grand theory designed to explain all behavior. He started developing his theory shortly after he began working at Yale University, drawing on ideas from a number of other thinkers including Charles Darwin, Ivan Pavlov , John. B. Watson , and Edward L. Thorndike .

Hull based his theory on the concept of homeostasis , the idea that the body actively works to maintain a certain state of balance or equilibrium. For example, your body regulates its temperature in order to ensure that you don't become too hot or too cold. Hull believed that behavior was one of the ways that an organism maintains this balance.

Based on this idea, Hull suggested that all motivation arises as a result of these biological needs. In his theory, Hull used the term drive to refer to the state of tension or arousal caused by biological or physiological needs. Thirst, hunger, and the need for warmth are all examples of drives. A drive creates an unpleasant state, a tension that needs to be reduced.

In order to reduce this state of tension, humans and animals seek out ways to fulfill these biological needs. We get a drink when we are thirsty. We eat when we are hungry. We turn up the thermostat when we are cold. He suggested that humans and animals will then repeat any behavior that reduces these drives.

Hull is considered a neo-behaviorist thinker, but like the other major behaviorists, he believed that human behavior could be explained by conditioning and reinforcement.

According to Hull, the reduction of the drive acts as a reinforcement for that behavior.

This reinforcement increases the likelihood that the same behavior will occur again in the future when the same need arises. In order to survive in its environment, an organism must behave in ways that meet these survival needs.

"When survival is in jeopardy, the organism is in a state of need (when the biological requirements for survival are not being met) so the organism behaves in a fashion to reduce that need," Hull explained.

In a stimulus-response (S-R) relationship, when the stimulus and response are followed by a reduction in the need, it increases the likelihood that the same stimulus will elicit the same response again in the future.

Hull's Drive Reduction Formula

Hull's goal was to develop a theory of learning that could be expressed mathematically, to create a "formula" to explain and understand human behavior.

Mathematical Deductive Theory of Behavior

sEr = V x D x K x J x sHr - sIr - Ir - sOr - sLr

• sEr: Excitatory potential, or the likelihood that an organism will produce a response (r) to a stimulus (s)
• V: Stimulus intensity dynamism, meaning some stimuli will have greater influences than others
• D: Drive strength, determined by the amount of biological deprivation
• K: Incentive motivation , or the size or magnitude of the goal
• J: The delay before the organism is allowed to seek reinforcement
• sHr: Habit strength, established by the amount of previous conditioning
• slr: Conditioned inhibition, caused by previous lack of reinforcement
• lr: Reactive inhibition, or fatigue
• sOr: Random error
• sLr: Reaction threshold, or the smallest amount of reinforcement that will produce learning

Hull's approach was viewed by many as overly complex, yet at the same time, critics suggested that the drive reduction theory failed to fully explain human motivation. His work did, however, have an influence on psychology and future theories of motivation.

Criticism of Drive Reduction Theory

While Hull's theory was popular during the middle part of the 20th century, it began to fall out of favor for a number of reasons. Starting as early as the 1950s, critics began pointing out the flaws in the drive reduction approach.

Lack of Generalizability

Because of his emphasis on quantifying his variables in such a narrowly defined way, his theory lacks generalizability.

However, his emphasis on rigorous experimental techniques and scientific methods did have an important influence on the field of psychology.

Does Not Address Secondary Reinforcers

One of the biggest problems with Hull's drive reduction theory is that it does not account for how secondary reinforcers reduce drives.

Unlike primary drives such as hunger and thirst, secondary reinforcers do nothing to directly reduce physiological and biological needs. Take money, for example. While money does allow you to purchase primary reinforcers, it does nothing in and of itself to reduce drives. Despite this, money still acts as a powerful source of reinforcement.

Does Not Fully Explain Behavior

Another major criticism of the drive reduction theory of learning is that it does not explain why people engage in behaviors that do not reduce drives. For example, people often eat when they’re not hungry or drink when they’re not thirsty.

In some cases, people actually participate in activities that increase tension such as sky-diving or bungee jumping. Why would people seek out activities that do nothing to fulfill biological needs and that actually place them in considerable danger? Drive reduction theory cannot account for such behaviors.

Impact of Drive Reduction Theory

While Hull's theory has largely fallen out of favor in psychology, it is still worthwhile to understand the effect it had on other psychologists of the time and how it helped contribute to later research in psychology.

In order to fully understand the theories that came after it, it's important for students to grasp the basics of Hull’s theory.

For example, many of the motivational theories that emerged during the 1950s and 1960s were either based on Hull's original theory or were focused on providing alternatives to the drive reduction theory.

Alternatives to Drive Reduction Theory

Other theories of motivation that have been proposed include:

• Arousal theory suggests that people are motivated to engage in behaviors to maintain a certain level of physiological arousal. The ideal level varies from person to person, leading people to seek stimulation or relaxation depending on what they need.
• Maslow's hierarchy of needs emerged as an alternative to Hull's approach. and suggests that human behavior is motivated by certain physiological and psychological needs. These needs begin with the most basic and progress to more complex ones.
• Incentive theory proposes that behaviors are motivated by external incentives. It suggests that what we do is directly influenced by external rewards. For example, you study to get a good grade or put in extra effort at work to receive a bonus.
• Self-determination theory suggests that people are motivated by the need to experience autonomy, competence, and connection. People want to feel in control of their actions, strive to become skilled in those actions, and need to experience a sense of belonging .

Other researchers have proposed a modern reformulation of Hull's ideas that remedies some of the original theory's failings.

Drive reductions theory suggests that the actions we take are motivated by a need to reduce the tension created by physiological drives. The theory is founded on the concept of homeostasis, or the need to maintain a state of equilibrium in the body.

This theory had an important influence in psychology, particularly in understanding how physiological states can play a role in motivating human behavior. However, the theory has been replaced by others since it does not adequately account for the complex cognitive, social, psychological, and cultural factors that can play a role in motivating our actions.

Stults-Kolehmainen MA. Humans have a basic physical and psychological need to move the body: Physical activity as a primary drive .  Front Psychol . 2023;14:1134049. doi:10.3389/fpsyg.2023.1134049

Littman RA, Wade EA. A negative test of the drive-reduction hypothesis . Quarterly Journal of Experimental Psychology . 1955;7(2):56-66. doi:10.1080/17470215508416675

Keramati M, Gutkin B. Homeostatic reinforcement learning for integrating reward collection and physiological stability .  Elife . 2014;3:e04811. doi:10.7554/eLife.04811

American Psychological Association. Arousal theory .

Ryan RM, Deci EL.  Intrinsic and extrinsic motivation from a self-determination theory perspective: Definitions, theory, practices, and future directions .  Contemp Educ Psychol . 2020;61:101860. doi:10.1016/j.cedpsych.2020.101860

• Hull CL. The Conflicting Psychologies of Learning: A Way Out . Psychological Review . 1935;42:491-516.
• Schultz DP, Schultz SE. A History of Modern Psychology. 11th ed. Cengage Learning; 2016.

By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."

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Empirical Approaches to Altruism

Many philosophers have maintained that altruism is a crucial component of morality, and that people often do behave altruistically. Other philosophers, along with many biologists and social scientists, have claimed that facts about human psychology, or about the evolutionary processes that have shaped human psychology, indicate that no human behavior is genuinely altruistic. Part of this disagreement can be traced to the fact that both philosophers and scientists use the term “altruism” with many quite different meanings. Sections 2, 3 and 4, set out a number of widely used accounts of altruism. One of these, “the standard account”, has been the focus of most of the debate in philosophy over the existence of altruism. Sections 5 and 6, review some of the most important empirical work aimed at determining whether humans can indeed behave altruistically, on the standard account.

1. Some Philosophical Background

2. defining “egoism” and “altruism”—the standard account, 3. altruism and evolution, 4. altruism in the social sciences, 5.1 the social punishment hypothesis, 5.2 the aversive-arousal reduction hypothesis, 5.3 the challenge posed by “self-other merging”, 5.4 have batson’s studies made a convincing case for the existence of altruism in humans, 6. beyond egoism vs. altruism, 7. the bottom line, other internet resources, related entries.

People often behave in ways that benefit others, and they sometimes do this knowing that it will be costly, unpleasant or dangerous. But at least since Plato’s classic discussion in the second Book of the Republic , debate has raged over why people behave in this way. Are their motives really altruistic, or is their behavior ultimately motivated by self-interest? Famously, Hobbes gave this answer:

No man giveth but with intention of good to himself, because gift is voluntary; and of all voluntary acts, the object is to every man his own good; of which, if men see they shall be frustrated, there will be no beginning of benevolence or trust, nor consequently of mutual help. (1651 [1981]: Ch. 15)

Views like Hobbes’ have come to be called egoism , [ 1 ] and this rather depressing conception of human motivation has apparently been favored, in one form or another, by a number of eminent philosophical advocates, including Bentham, J.S. Mill and Nietzsche. [ 2 ] Egoism was also arguably the dominant view about human motivation in the social sciences for much of the twentieth century (Piliavin & Charng 1990: 28; Grant 1997). Dissenting voices, though perhaps fewer in number, have been no less eminent. Butler, Hume, Rousseau, and Adam Smith have all argued that, sometimes at least, human motivation is genuinely altruistic.

Though the issue dividing egoistic and altruistic accounts of human motivation is largely empirical, it is easy to see why philosophers have thought that the competing answers will have important consequences for moral theory. For example, Kant famously argued that a person should act “not from inclination but from duty, and by this would his conduct first acquire true moral worth” (1785 [1949]: Sec. 1, parag. 12). But egoism maintains that all human motivation is ultimately self-interested, and thus people can’t act “from duty” in the way that Kant urged. Thus if egoism is true, Kant’s account would entail that no conduct has “true moral worth”. Additionally, if egoism is true, it would appear to impose a strong constraint on how a moral theory can answer the venerable question “Why should I be moral?” since, as Hobbes clearly saw, the answer will have to ground the motivation to be moral in the agent’s self-interest.

There are related implications for political philosophy. If the egoists are right, then the only way to motivate prosocial behavior is to give people a selfish reason for engaging in such behavior, and this constrains the design of political institutions intended to encourage civic-minded behavior. John Stuart Mill, who was both a utilitarian and an egoist, advocated a variety of manipulative social interventions to engender conformity with utilitarian moral standards from egoistic moral agents. [ 3 ]

It is easy to find philosophers suggesting that altruism is required for morality or that egoism is incompatible with morality—and easier still to find philosophers who claim that other philosophers think this. Here are a few examples culled from a standard reference work that happened to be close at hand:

Moral behavior is, at the most general level, altruistic behavior, motivated by the desire to promote not only our own welfare but the welfare of others. (Rachels 2000: 81) [O]ne central assumption motivating ethical theory in the Analytic tradition is that the function of ethics is to combat the inherent egoism or selfishness of individuals. Indeed, many thinkers define the basic goal of morality as “selflessness” or “altruism”. (W. Schroeder 2000: 396) Philosophers since Socrates worried that humans might be capable of acting only to promote their own self-interest. But if that is all we can do, then it seems morality is impossible. (LaFollette 2000a: 5) [ 4 ]

While the egoism/altruism debate has historically been of great philosophical interest, the issue centrally concerns psychological questions about the nature of human motivation, so it’s no surprise that psychologists have done a great deal of empirical research aimed at determining which view is correct. The psychological literature will be center-stage in section 5 , the longest section in this entry, and in section 6 . But before considering the empirical literature, it is important to be clear on what the debate is about.

Providing definitions for “egoism” and “altruism” is a contentious matter, since these terms have been understood in radically different ways both in philosophy and in the biological and social sciences. In this entry the focus will be on the most widespread interpretation of “egoism” and “altruism”, understood as descriptive claims about human psychology, within philosophy. We’ll call it “the standard account”, versions of which have been offered by numerous authors including Broad (1950), Feinberg (1965 [1999]), Sober and Wilson (1998: Chs. 6 & 7), Rachels (2003: Ch. 6), Joyce (2006: Ch. 1), Kitcher (2010, 2011: Ch. 1), May (2011a), and many others. Not surprisingly, there are minor differences among the accounts provided by these authors, and those differences occasionally provoke disagreement in the literature. But all of them bear a strong family resemblance to the one we’re about to sketch. [ 5 ]

At the end of this section, a different account of altruism proposed in philosophy is briefly discussed. Biological accounts of altruism will be considered in section 3 , and accounts proposed by social scientists will be discussed in section 4 . But our present focus is the standard philosophical account.

As already intimated, while advocates of altruism and of egoism agree that people often help others, they disagree about why they do this. On the standard account, defenders of altruism insist that, sometimes at least, people are motivated by an ultimate desire for the well-being of another person, while defenders of egoism maintain that all ultimate desires are self-interested. This formulation invites questions about (1) what it is for a behavior to be motivated by an ultimate desire , and (2) the distinction between desires that are self-interested and desires for the well-being of others .

The first question, regarding ultimate desires, can be usefully explicated with the help of a familiar account of practical reasoning . [ 6 ] On this account, practical reasoning is a causal process via which a desire and a belief give rise to or sustain another desire. For example, a desire to drink an espresso and a belief that the best place to get an espresso is at the espresso bar on Main Street may cause a desire to go to the espresso bar on Main Street. This desire can then join forces with another belief to generate a third desire, and so on. Sometimes this process will lead to a desire to perform a relatively simple or “basic” action, and that desire, in turn, will cause the agent to perform the basic action without the intervention of any further desires. Desires produced or sustained by this process of practical reasoning are instrumental desires—the agent has them because she thinks that satisfying them will lead to something else that she desires. But not all desires can be instrumental desires. If we are to avoid circularity or an infinite regress there must be some desires that are not produced because the agent thinks that satisfying them will facilitate satisfying some other desire. These desires that are not produced or sustained by practical reasoning are the agent’s ultimate desires, and the objects of ultimate desires—the states of affairs desired—are often said to be desired “for their own sake”. A behavior is motivated by a specific ultimate desire when that desire is part of the practical reasoning process that leads to the behavior.

Although the second question, about the distinction between self-interested desires and desires for the well-being of others, would require an extended discussion in any comprehensive treatment of the debate between egoists and altruists, some rough and ready examples of the distinction will suffice here. [ 7 ] The desires that another person’s life be saved, that another person’s suffering be alleviated, or that another person be happy are paradigm cases of desires for the well-being of others, while desires to experience pleasure, get rich, and become famous are typical examples of self-interested desires. The self-interested desires to experience pleasure and to avoid pain have played an especially prominent role in the debate, since one version of egoism, often called hedonism , maintains that these are our only ultimate desires. Stich et al. (2010) maintain that some desires, like the desire that I myself be the one to alleviate my friend’s suffering, are hard to classify, and conclude that both egoism and altruism are best viewed as somewhat vague. [ 8 ]

Whether or not this is correct, it is clear that there are many desires that are neither self-interested nor desires for the well-being of others. One of the earliest examples was provided by Bishop Joseph Butler (1726 [1887]) who noted that revenge often engenders malevolent desires, like the desire that another person be harmed, which are obviously not desires for the well-being of the that person, and are not self-interested either. [ 9 ] Other examples include the desire that great works of art be preserved and the desire that space exploration be pursued. More interesting for moral theory are the desire to do one’s moral duty, and the desire to obey God’s commandments. If people have ultimate desires like these, then egoism is false. But, of course, the existence of ultimate desires like these would not show that altruism is true. The take-away from such cases is that on the standard account, egoism and altruism might both be mistaken.

Though interpretations of “altruism” in the standard account family predominate in the philosophical literature, some philosophers use the term in a very different way. A paper by Thomas Schramme (2017) provides a clear example.

[A]ltruism need not be reduced to its opposition to egoism. In this chapter, altruism is discussed as a psychological basis for moral conduct more generally, not just in terms of motivations to benefit others. Here altruism stands for the capacity to take the moral point of view and be disposed to act accordingly…. Seen in this way, altruism is a short word for the psychological phenomenon of the internalized pull of morality… (2017: 203–204). Altruism is then basically identical with taking the moral point of view, i.e., an individual appreciation of the normative force of morality. (2017: 209). [ 10 ]

Schramme is, of course, aware that many authors reject “such a close connection of general moral motivation and altruistic motivation” but he maintains that this account of altruism “can certainly be found in the philosophical debate” (2017: 209). Much the same claim is made by Badhwar (1993: 90):

In the moral philosophy of the last two centuries, altruism of one kind or another has typically been regarded as identical with moral concern.

Schramme is surely right that

[t]he fact that we can understand altruism both as referring to moral behavior quite generally and as restricted to a more specific set of helping behaviors may lead to confusion. (2017: 204)

Though some philosophers may believe there is a substantive dispute about which account of altruism is correct, others think that the issue is purely terminological. As noted earlier, the primary concern in this entry is with what this entry dubs the “standard account” of altruism. But in the next two sections a number of accounts are considered that differ both from the standard account and from the account discussed by Schramme and Badhwar.

Readers familiar with some of the popular literature on the evolution of morality that has appeared in the last few decades might suspect that recent work in evolutionary biology has resolved the debate between egoists and altruists. For some readers—and some writers—seem to interpret evolutionary theory as showing that altruism is biologically impossible. If altruistic organisms were somehow to emerge, this literature sometimes suggests, they would lose the competition for survival and reproduction to their selfish conspecifics, and they would quickly become extinct. On this view, any appearance of altruism is simply an illusion. In the memorable words of biologist Michael Ghiselin (1974: 247) “Scratch an ‘altruist’ and watch a ‘hypocrite’ bleed”.

But as Sober and Wilson (1998) have argued with great clarity, there is no simple connection between evolutionary theory and the philosophical debate between egoism and altruism. This is because the concept of altruism that is important in evolutionary theory is quite different from the standard concept of altruism invoked in the philosophical debate. For biologists, an organism behaves altruistically if and only if the behavior in question reduces its own fitness while increasing the fitness of one or more other organisms. Roughly speaking, an organism’s fitness is a measure of how many descendants it will have. [ 11 ] As Sober and Wilson note, on this evolutionary account of altruism, an organism can be altruistic even if it does not have a mind capable of having beliefs and desires. Thus there can be no easy inference from biological altruism to psychological altruism. Nor does the inference go in the opposite direction. To make the point, Sober and Wilson (Ch. 10) note that natural selection might well equip humans or other psychologically sophisticated organisms with ultimate desires to foster the welfare of their offspring under certain circumstances. Organisms with these ultimate desires would be psychological altruists, though the behavior that the desires gave rise to would typically not be evolutionarily altruistic, since by helping their offspring organisms typically are increasing their own fitness. So, contrary to the presumption that evolutionary biology has resolved the debate between egoists and altruists in favor of egoism, it appears that evolutionary theory little to offer that will support that conclusion. [ 12 ]

In recent decades there has been an enormous amount of discussion of altruism in psychology, sociology, economics, anthropology and primatology. Much of the work in psychology, including all of the work recounted in section 5 , has adopted the “standard account” of altruism. But some psychologists, and many researchers in other disciplines, have something very different in mind. In a useful review of recent discussions of altruism, Clavien and Chapuisat lament the fact that

[t]he notion of altruism has become so plastic that it is often hard to understand what is really meant by the authors using the term, and even harder to evaluate the degree to which results from one research field—e.g., experimental economics—may facilitate the resolution of debates in another research field—e.g., evolutionary biology or philosophy. (2013: 134)

One of the notions that Clavien and Chapuisat find playing a role in evolutionary anthropology, evolutionary game theory and experimental economics is what they call “preference altruism”. “An action is altruistic”, in this sense, “if it results from preferences for improving others’ interests and welfare at some cost to oneself” (2013: 131). Though the agent’s psychology is relevant, on this account of altruism, there is no mention of the agent’s ultimate desires. Thus an action can be preference altruistic even if the agent’s preference for improving someone else’s welfare is an instrumental preference engendered by the belief that improving the recipient’s welfare will contribute to the agent’s own pleasure or treasure.

A second, quite different, concept of altruism invoked in these disciplines is what Clavien and Chapuisat call “behavioral altruism”. On this interpretation of altruism, an agent’s psychology plays no role in determining whether her action is altruistic.

A behavior is altruistic if it brings any kind of benefit to other individuals at some cost for the agent, and if there is no foreseeable way for the agent to reap compensatory benefits from her behavior. (2013: 131)

Ramsey (2016) makes a plausible case that some eminent primatologists and psychologists (including de Waal (2008) and Warneken and Tomasello (2008)) invoke an even less demanding account of altruism, one that requires that the recipient benefit but drops the requirement that altruistic behavior must involve some cost to the agent. Ramsey labels this notion “helping altruism”.

Combining accounts from philosophy, biology and the social sciences, Piccinini and Schulz (2019) offer a multidimensional taxonomy for different accounts of altruism, and argue that the distinctions they draw are essential for assessing the moral status of different kinds of altruism.

In reviewing the many different ways in which the term “altruism” has been used in the empirical and philosophical literature, it is hard to resist allusions to the biblical Tower of Babel. But for the remainder of this entry, these interpretations of “altruism” will be left behind. From here on, the focus will be on altruism as it is understood in the standard account.

5. The Egoism vs. Altruism Debate in Psychology

The psychological literature relevant to the egoism vs. altruism debate is vast; [ 13 ] in the interests of a tolerable brevity, the entry will focus on the work of Daniel Batson and his associates, who have done some of the most influential and philosophically sophisticated work in this area.

Batson, along with many other researchers, begins by borrowing an idea that has deep roots in philosophical discussions of altruism. Though the details and the terminology differ significantly from author to author, the core idea is that altruism is often the product of an emotional response to the distress of another person. Aquinas (1270 [1917]: II–II, 30, 3), for example, maintains that

mercy is the heartfelt sympathy for another’s distress, impelling us to succour him if we can.

And Adam Smith (1759 [1853]: I, I, 1. 1) tells us that

pity or compassion [is] the emotion we feel for the misery of others, when we either see it, or are made to conceive it in a very lively manner

and these emotions

interest [man] in the fortunes of others, and render their happiness necessary to him, though he derives nothing from it except the pleasure of seeing it.

Batson (1991: 58) labels this response “empathy” which he characterizes as “an other-oriented emotional reaction to seeing someone suffer”, and calls the traditional idea that empathy leads to altruism the empathy-altruism hypothesis. On Batson’s account (1991: 86), empathy

includes feeling sympathetic, compassionate, warm, softhearted, tender, and the like, and according to the empathy-altruism hypothesis, it evokes altruistic motivation

though that motivation does not always lead to behavior. Batson (1991: 117) contrasts empathy with a cluster of affective responses he calls “personal distress” which is “made up of more self-oriented feelings such as upset, alarm, anxiety, and distress”. [ 14 ]

If the philosophical tradition that suggests the empathy-altruism hypothesis is on the right track, and Batson believes it is, one would predict that when people feel empathy they will desire to help those who evoke the emotion, and thus be more inclined to engage in helping behavior than people who do not feel empathy. This does not mean that people will always engage in helping behavior when they feel empathy, since people may often have conflicting desires, and not all conflicts are resolved in favor of empathy’s urgings. Nor does it mean that when people feel little or no empathy they will not engage in helping behavior, since the desire to help can also be produced by a variety of processes in which empathy plays no role. But we should expect that typically people feeling empathy will be more likely to help than people who aren’t feeling empathy, and the stronger their feelings of empathy the more likely it is that they will engage in helping behavior.

In order to put this claim to empirical test, it is important to have ways of inducing empathy in the laboratory, and there is a substantial body of literature suggesting how this can be done. For example, Stotland (1969) showed that subjects who were instructed to imagine how a specified person (often called “the target”) felt when undergoing what subjects believed to be a painful medical procedure reported stronger feelings of empathy and showed greater physiological arousal than subjects who were instructed to watch the target person’s movements. [ 15 ] Relatedly, Krebs (1975) demonstrated that subjects who observe someone similar to themselves undergo painful experiences show more physiological arousal, report identifying with the target more strongly, and report feeling worse while waiting for the painful stimulus to begin than do subjects who observe the same painful experiences administered to someone who is not similar to themselves. Krebs also showed that subjects are more willing to help at some personal cost when the sufferer is similar to themselves. Batson (1991: 82–87) interprets these findings as indicating that people are more inclined to feel empathy for those they believe to be similar to themselves, and thus that empathy can often be induced by providing a person with evidence that she and a target person are similar.

To make the case that empathy leads to helping behavior, Batson relies in part on work by others, including the just-cited Krebs (1975) study and a study by Dovidio et al. (1990). In that latter study, Stotland’s technique for manipulating empathy by instructing subjects to take the perspective of the person in distress was used to induce empathy for a young woman. Subjects focused on one of two quite different problems that the young woman faced. When given an opportunity to help the young woman, subjects in whom empathy had been evoked were more likely to help than subjects in a low empathy condition, and the increase in helping was specific to the problem that had evoked the empathy.

Many of Batson’s own experiments, some of which are described below, also support the contention that both spontaneously evoked empathy and empathy engendering experimental manipulations increase the likelihood of helping behavior. Another important source of support for the link between empathy and helping behavior is a meta-analysis of a large body of experimental literature by Eisenberg and Miller (1987) which found positive correlations between empathy and prosocial behavior in studies using a variety of techniques to assess empathy. On the basis of these and other findings, Batson (1991: 95) argues that

there is indeed an empathy-helping relationship; feeling empathy for a person in need increases the likelihood of helping to relieve that need.

It might be thought that establishing a causal link between empathy and helping behavior would be bad news for egoism. But, as Batson makes clear, the fact that empathy leads to helping behavior does not resolve the dispute between egoism and altruism, since it does not address the nature of the motivation for the helping behavior that empathy evokes. One possibility is that empathy does indeed cause a genuinely altruistic desire to help—an ultimate desire for the well-being of the sufferer. But there are also a variety of egoistic routes by which empathy might lead to helping behavior. Perhaps the most obvious of these is that empathy might simply be (or cause) an unpleasant experience, and that people are motivated to help because they believe this is the best way to stop the unpleasant experience that is caused by someone else’s distress.

Quite a different family of egoistic possibilities focus on the rewards to be expected for helping and/or the punishments to be expected for withholding assistance. If people believe that others will reward or sanction them for helping or failing to help in certain circumstances, and that the feeling of empathy marks those cases in which social sanctions or rewards are most likely, then we would expect people to be more helpful when they feel empathy, even if their ultimate motivation is purely egoistic. A variation on this theme focuses on rewards or punishments that are self-administered. If people believe that helping may make them feel good, or that failing to help may make them feel bad, and that these feelings will be most likely to occur in cases where they feel empathy, then once again we would expect people who empathize to be more helpful, though their motives may be not at all altruistic.

During the last four decades, Batson and his collaborators have systematically explored these egoistic hypotheses and many others. Their strategy is to design experiments in which the altruistic explanation of the link between empathy and helping can be compared to one or another specific egoistic explanation. Reviewing all of these experiments would require a far longer entry. [ 16 ] Instead the focus will be on two clusters of experiments that illustrate the potential philosophical rewards of designing and interpreting experiments in this area, as well as some difficulties with the project.

One of the more popular egoist alternatives to the empathy-altruism hypothesis is the idea that people engage in helping behavior because they fear that other people will punish them if they do not. If I don’t help, the actor is supposed to worry, people will be angry or they will think badly of me, and this may have negative effects on how they treat me in the future. As it stands, this egoist hypothesis can’t explain the fact that empathy increases the likelihood of helping, but a more sophisticated version is easy to construct by adding the assumption that people think social sanctions for not helping are more likely when the target engenders empathy.

To test this hypothesis—which Batson calls the socially administered empathy-specific punishment hypothesis —against the empathy-altruism hypothesis, Batson and his associates (Fultz et al. 1986) designed an experiment in which they manipulated both the level of empathy that subjects felt for the target and the likelihood that anyone would know whether or not the subject had opted to help a person in need. Others can form a negative evaluation of your decision not to help only if they know the choice you are facing and the decision you have made; if your decision is secret, you need have no fear of social sanctions. Thus the socially administered empathy-specific punishment hypothesis predicts that subjects who exhibit high empathy on a given occasion will be more likely to help when they believe others will know if they fail to do so. On the empathy-altruism hypothesis, by contrast, high empathy subjects are motivated by an ultimate desire to help, and thus their helping levels should be high whether or not others would know if they decided not to help. In the low empathy condition, both hypotheses predict that levels of helping will be low. These predictions are summarized in Tables 1 and 2.

Low High Low Low Table 1. Predictions About the Amount of Helping (Low or High) on the Socially Administered Empathy-Specific Punishment Hypothesis. Low High Low High Table 2. Predictions About the Amount of Helping (Low or High) on the Empathy-Altruism Hypothesis. Subjects in the experiment were told that they were participating in an impression formation study, and that they had been randomly assigned to the role of “listener” in which they would read confidential notes from another student participant, the “communicator”. They were given two notes from Janet Arnold, an out-of-state freshman who reveals that she is very lonely and hoping to find a friend. After completing a form on which subjects indicated their impressions of Janet and their emotional responses to her note, they were presented with an unexpected opportunity to befriend Janet by volunteering to take part in a study of long-term relationships involving an initial meeting with Janet and periodic phone interviews about the development of their friendship. Participants who were willing to help were asked how much time they were willing to spend with Janet during the next month. To manipulate empathy, Batson and his associates used the Stotland technique. Subjects assigned to the low-empathy condition were instructed to Read the information in the communicator’s notes carefully, trying to be as objective as possible. Try to focus on the techniques used to get the communicator’s message across. Subjects assigned to the high-empathy condition were instructed to Read the information in the communicator’s notes carefully, trying to take the perspective of the individual writing the notes. Try to imagine how this individual feels about what he or she writes. (1991: 132) Four steps were taken to manipulate the perceived potential for negative social evaluation. In the low-potential condition (1991: 132): Subjects were told that they would be the only person ever to read the communicator’s notes, and the notes were delivered in a sealed envelope. Subjects were assured that the questionnaires reporting their reactions to Janet’s note would be anonymous. Subjects’ responses to the invitation to participate in the long-term relationship study were returned to the professor in a sealed envelope, so no one would know if they did not want to help Janet. (Since they believed the professor had not read Janet’s note, they could be expected to surmise that he would not know that Janet needed a friend.) In the letter inviting them to participate in the relationship study, subjects were told that Janet would be contacted “only if you want a meeting; if you do not, then we will not contact the communicator and he or she will not know that you were ever asked about actually meeting”. In the high-potential condition (1991: 133): Subjects were told that the experimenter would read the communicator’s notes. Also, the experimenter would collect the questionnaire when the subject completed it and would compare the content of the notes with the impressions the subject formed. No envelope was provided for their response to the invitation to participate in the long-term relationship study, so subjects could infer that the experimenter would know about Janet’s need for a friend, about their emotional reaction to Janet, and would also know whether or not they had agreed to help Janet. Subjects were told that Janet would know if they decided not to help. As Batson notes, procedures in the high-potential condition were designed to highlight the possibility of negative social evaluation if the participant decided not to volunteer to spend time with Janet. 0.67 1.71 1.29 2.44 Table 3. Amount of Help Offered Janet, given as the mean amount of time participants offered to spend with Janet (Fultz et al. 1986, Study 2) The results, given in Table 3, indicate that the socially administered empathy-specific punishment hypothesis did not fare well. On the basis of this experiment and a similar experiment in which empathy for Janet was not manipulated but was measured by self-report, Batson concludes that the socially administered empathy-specific punishment hypothesis is not consistent with the experimental facts. Contrary to what the social-evaluation version of the empathy-specific punishment hypothesis predicted, eliminating anticipated negative social evaluation in these two studies did not eliminate the empathy-helping relationship. Rather than high empathy leading to more help only under high social evaluation, it led to more helping under both low and high social evaluation. This pattern of results is not consistent with what would be expected if empathically aroused individuals are egoistically motivated to avoid looking bad in the eyes of others; it is quite consistent with what would be expected if empathy evokes altruistic motivation to reduce the victim’s need (Batson 1991: 134). Though two experiments hardly make a conclusive case, these studies make the socially administered empathy-specific punishment hypothesis look significantly less plausible than the empathy-altruism hypothesis. So one popular egoist hypothesis has been dealt a serious blow: high empathy subjects were more likely to help whether or not they could expect their behavior to be socially scrutinized. At least in some circumstances, empathy appears to facilitate helping independently of the threat of social sanction. Another popular egoistic strategy for explaining the link between empathy and helping behavior is the aversive-arousal reduction hypothesis , which maintains that witnessing someone in need, and the empathy it evokes, is an unpleasant or aversive experience, and that helping is motivated by the desire to diminish that aversive experience. [ 17 ] If this is right, Batson maintains, people in a high empathy condition will sometimes have two quite different ways of reducing the aversive experience—they can help the person in need or they can simply leave . Which strategy a person adopts will depend, in part, on how difficult or costly it is to depart the scene. If escape is easy, people will be more likely to take that option, while if leaving is more difficult people will be more likely to help, since that is a less costly way of ending the aversive experience. If, on the other hand, the empathy-altruism hypothesis is correct and empathy leads to genuinely altruistic motivation, one would expect people in a high empathy condition to help whether escape is easy or hard, since only helping will satisfy an altruistic desire. Altruism and egoism both allow that even in the absence of empathy, an emotionally disturbing need situation will produce feelings of personal distress, thus they would both predict that people in a low empathy condition will be more inclined to help when escape is difficult, and less inclined when escape is easy. Batson summarizes these predictions in Tables 4 and 5 (Batson 1991: 111). Low Low High High/Very High Table 4. Predictions from the Aversive-Arousal Reduction Hypothesis for the Rate of Helping in an Escape X Empathy Design Low High High High Table 5. Predictions from the Empathy-Altruism Hypothesis for the Rate of Helping in an Escape X Empathy Design To test these predictions, Batson and his associates conducted a total of six experiments. In one of these (experiment 1 in Batson, Duncan, et al. 1981), student subjects were required to watch, via what they believed to be closed circuit TV transmission—actually a scripted video recording—as another student subject, Elaine—actually a confederate—attempted to perform a task while receiving electric shocks at random intervals. Observer subjects were told that their task would be to form and report an impression of how Elaine performs under aversive conditions. On the tape, Elaine is clearly finding the shocks very uncomfortable, and after her second trial at doing the task, she explains to Martha, the assistant administering the shocks, that she is unusually sensitive to mild electric shocks because of a childhood trauma. Martha then suggests that perhaps the observer subject might be willing to help Elaine by taking her place, and the experimenter asks whether the subject is willing to do that. To manipulate ease of escape, some subjects were told that if they decide not to take Elaine’s place, they will be required to watch eight additional trials, while other subjects were told that if they decide not to take Elaine’s place they are free to go. To manipulate the level of empathy that subjects feel for Elaine, subjects were given a copy of a personal values and interests questionnaire, allegedly filled out by Elaine, in order to help them form an impression of her performance. In the high empathy condition, Elaine’s values and interests were very similar to the subject’s (which had been determined in a screening session several weeks before), while in the low empathy condition, they were very different. The results, given in Table 6, clearly exhibit the pattern predicted by the empathy-altruism hypothesis, not the pattern predicted by the aversive-arousal reduction hypothesis. 0.18 0.91 0.64 0.82 Table 6. Proportion of Subjects Agreeing to Take Shocks for Elaine (Batson, Duncan, et al. 1981, Experiment 1) In additional experiments, Batson and his associates used four different techniques to create the low- and high-empathy conditions, two techniques for manipulating ease of escape, and two different need situations (Batson, Duncan, et al. 1981; Toi and Batson 1982; Batson, O’Quin et al. 1983). The results in all of these experiments exhibited the same pattern. Intriguingly, in another experiment, Batson and colleagues attempted to break the pattern by telling the subjects that the shock level they would have to endure was the highest of four options, “clearly painful but not harmful”. They reasoned that, under these circumstances, even if high empathy subjects had an ultimate desire to help, this desire might well be overridden by the desire to avoid a series of very painful shocks. As expected, the pattern of results in this experiment fit the pattern in Table 4 . These are impressive findings. Over and over again, in well designed and carefully conducted experiments, Batson and his associates have produced results which are clearly compatible with the predictions of the empathy-altruism hypothesis, as set out in Table 5 , and clearly incompatible with the predictions of the aversive-arousal reduction hypothesis, as set out in Table 4 . Even the “clearly painful shock” experiment, which produced results in the pattern of Table 4, are comfortably compatible with the empathy-altruism hypothesis; as noted earlier, the empathy-altruism hypothesis allows that high empathy subjects may have desires that are stronger than their ultimate desire to help the target, and the desire to avoid a painful electric shock is a very plausible candidate. There is, however, a problem to be overcome before one concludes that the aversive-arousal reduction hypothesis cannot explain the findings that Batson and his associates have reported. In arguing that Table 4 reflects the predictions made by the aversive-arousal reduction hypothesis, Batson must assume that escape will alleviate the aversive affect in both low & high empathy situations, and that subjects believe this (although the belief may not be readily available to introspection). One might call this the out of sight, out of mind assumption. Elaborating on an idea suggested by Hoffman (1991) and Hornstein (1991), an advocate of egoism might propose that although subjects do believe this when they have little empathy for the target, they do not believe it when they have high empathy for the target . Perhaps high empathy subjects believe that if they escape they will continue to be troubled by the thought or memory of the distressed target and thus that physical escape will not lead to psychological escape. Indeed, in cases where empathy is strong and is evoked by attachment, this is just what common sense would lead us to expect. Do you really believe that if your mother was in grave distress and you left without helping her you would not continue to be troubled by the knowledge that she was still in distress? We’re guessing that you don’t. But if the high-empathy subjects in Batson’s experiments believe that they will continue to be plagued by distressing thoughts about the target even after they depart, then the egoistic aversive-arousal reduction hypothesis predicts that these subjects will be inclined to help in both the easy physical escape and the difficult physical escape conditions, since helping is the only strategy they believe will be effective for reducing the aversive arousal. So neither the results reported in Table 6 nor the results of any of Batson’s other experiments would give us a reason to prefer the empathy-altruism hypothesis over the aversive-arousal reduction hypothesis, because both hypotheses make the same prediction. Is it the case that high empathy subjects in experiments like Batson’s believe that unless they help they will continue to think about the target and thus continue to feel distress, and that this belief leads to helping because it generates an egoistic instrumental desire to help? This is, of course, an empirical question, and a cleverly designed experiment by Stocks and his associates (Stocks et al. 2009) suggests that, in situations like those used in Batson’s experiments, a belief that they will continue to think about the target does not play a significant role in causing the helping behavior in high empathy subjects. Batson’s work on the aversive-arousal reduction hypothesis, buttressed by the Stocks et al. finding, is a major advance in the egoism vs. altruism debate. The aversive-arousal reduction hypothesis has been one of the most popular egoistic strategies for explaining helping behavior. But the experimental findings strongly suggest that in situations like those that Batson and his associates have studied, the empathy-altruism hypothesis offers a much better explanation of the subjects’ behavior than the aversive-arousal reduction hypothesis. As noted earlier, Batson and his colleagues have also designed experiments pitting the empathy-altruism hypothesis against a substantial list of other egoistic explanations for the link between empathy and helping behavior. In each case, the evidence appears to challenge the egoistic alternative, though as is almost always the case in empirical work of this sort, some researchers remain unconvinced. [ 18 ] There is however, an influential critique of Batson’s work that challenges all of his experimental work on the empathy-altruism hypothesis. It argues that empathy and its precursors alter people’s self-concept in a way that undermines the claim that their helping behavior is genuinely altruistic. During the last three decades, psychologists have devoted a great deal of effort to exploring how people think of the self. One major theme in this literature is that people’s conception of themselves varies across cultures, and that in many non-western cultures one’s social roles and one’s relation to other people play a much more central role in people’s self-concepts than they do in the individualistic West (Markus & Kitayama 1991; Baumeister 1998). One very simple way of studying these differences is to ask people to respond to the question “Who am I?” fifteen times. Non-westerners will typically mention social groups, group roles and relationships: “I am Maasai”, “I am a person who brings fruit to the temple”, “I am my father’s youngest son”. Westerners, by contrast, will typically mention personal attributes, aspirations and achievements: “I am intelligent”, “I am a pre-med student”, “I am the fastest swimmer in my school” (Ma & Schoeneman 1997). Another theme is that people’s conception of themselves is situationally malleable—it changes depending on who we are with, where we are and what we are doing (Kihlstrom & Cantor 1984; Markus & Wurf 1987). While this sort of situational malleability may not be surprising, a number of psychologists have suggested a much more radical situational malleability. Under certain circumstances, notably when we have a close personal relationship with another person, when we are trying to take the perspective of another person, or when we feel empathy for another person, the conceptual boundary between the self and the other person disappears; the self and the other merge. According to Arthur Aron and colleagues, Much of our cognition about the other in a close relationship is cognition in which the other is treated as self or confused with self—the underlying reason being a self-other merging. (Aron et al. 1980: 242) If this is true, then it poses a fundamental challenge to the claim that helping behavior directed at someone for whom we feel empathy is really altruistic. For, as Melvin Lerner memorably observed: It seems that we respond sympathetically, with compassion and a sense of concern, when we feel a sense of identity with the victim. In effect, we are reacting to the thought of ourselves in that situation. And, of course, we are filled with the “milk of human kindness” for our own sweet, innocent selves. (Lerner 1980: 77) A bit less colorfully, Batson notes that for “the contrast between altruism and egoism to be meaningful”, an individual providing help “must perceive self and other to be distinct individuals” (2011: 145–146). And if the distinction between self and other vanishes then so does the distinction between altruism and egoism, at least as these terms are used in the empathy-altruism hypothesis. (2011: 148) Psychologists who have debated the rather astonishing claim that people who provide help to others often lose track of the distinction between themselves and the person being helped have proposed several different ways of determining whether this sort of “self-other merging” has occurred. Before considering these, however, we should remind ourselves of an important philosophical distinction that will be crucial in assessing tests for self-other merging. [ 19 ] The distinction is often made using the labels “qualitative identity” and “numerical identity”. Qualitative identity is the relation that often obtains between two TV sets manufactured by the same company. They share most of their important properties. Numerical identity is a relationship that obtains between a person at one time in his life and that same person at another time in his life. If the time gap is substantial, the person at the earlier time may differ in many ways from the person at the later time. When you were a baby, you weighed less than 10 kg, spoke no language, and couldn’t walk. But you now are numerically the same person as the baby. Numerical identity can be of enormous legal and moral importance, a point nicely illustrated by the trial of John Demjanuk, the Ukrainian-born auto worker who was accused of being the sadistic Nazi concentration camp guard whose victims called him “Ivan the Terrible”. The man on trial, in 1988, differed in many ways from the concentration camp guard: he was much older, heavier, bald, and spoke English. He was obviously not even close to being qualitatively identical with perpetrator of Ivan’s crimes. What the court had to determine was not whether Ivan and Demjanuk were qualitatively identical but whether they were numerically identical. [ 20 ] What makes this distinction important for present purposes is that the sort of identity that is relevant to the debate between egoists and altruists is numerical identity, not qualitative identity. If Sophia, at age 30, sets aside a large sum of money that will be paid to Sophia at age 70, young Sophia is not being altruistic. If her ultimate goal is to ensure that old Sophia has the means to live a comfortable life, then young Sophia’s action is straightforwardly egoistic. The take-home message here is that if a test used to determine whether person A takes herself to be identical to person B is to be relevant to the egoism versus altruism debate, the test must provide evidence that person A takes herself to be numerically identical to person B , not that she takes herself to be qualitatively identical to person B . Now let’s consider how psychologists have attempted to assess whether experimental participants feel a sense of identity with someone they might be called on to help. In one of the most influential studies claiming to show that helping is often the product of a feeling of oneness, Cialdini et al. (1997) used a pair of tests. [P]articipants rated the extent of oneness they felt with the [person they might help] by responding to two items that were combined in all analyses to form a oneness index. The first item incorporated the Inclusion of Other in Self (IOS) Scale used by Aron et al. (1992) to measure self-other boundary overlap. It consisted of a set of seven pairs of increasingly overlapping circles. Participants selected the pair of circles that they believed best characterized their relationship with the [person they might help]. The second item asked participants to indicate on a 7-point scale the extent to which they would use the term we to describe their relationship with the [person they might help]. (1997: 484) In a critique of the Cialdini et al. paper, Batson, Sager, et al. (1997) used three measures of self-other merging. One was the IOS Scale used by Cialdini et al. The second was a “perceived similarity” task in which “[p]articipants were asked, ‘How similar to you do you think the person …is?’ (1 = somewhat, 9 = extremely)” (1997: 500). In the third, participants rated both themselves and the target on a series of personal attributes. The “measure of merging was the mean absolute difference between ratings of self and other” (1997: 498). It does not seem that any of these four tests of self-other merging provide a reason to believe that the participant views herself as numerically identical with another person. Indeed, both the perceived similarity test and the personal attribute rating test seem to be assessing qualitative identity rather than numerical identity. And it is far from clear what, if anything, the other two tests are measuring. So it seems that there is really no evidence at all that people in close relationships lose track of the distinction between themselves and another person. Indeed, as May notes, if someone really did believe that he exists in two obviously distinct bodies, the most natural conclusion to draw would be that he is delusional (May 2011b: 32). While the literature on self-other merging provides little reason to believe that normal people take themselves to be numerically identical with another person, it does provide a different kind of challenge to the empathy-altruism hypothesis defended by Batson and his colleagues. That hypothesis, it will be recalled, is that empathy often causes an ultimate desire to help another person. But in the Cialdini et al. (1977) paper cited earlier, they report three studies indicating that empathy, though it does occur, is not playing any causal role in the process that leads to helping. Rather, they maintain, it is “merging”—which is used here as a label for whatever the IOS scale and the use-of- we test measure—that is actually leading participants to help. Though the Cialdini et al. paper is quite sophisticated, Batson et al. (1997) pointed out a number of methodological problems. When they conducted a pair of experiments that avoided these methodological problems, the role of empathy in producing helping behavior was clearly evident. However, most experiments exploring the link between empathy and helping behavior, including this one, use a relatively small number of participants. And the “replication crisis” that has emerged in recent years has led many to worry about the robustness of the effects reported in experiments like these (Chambers 2017). McAuliffe et al. (2018) have addressed these concerns. Their high powered, pre-registered study, run on the internet, analyzed data from 680 participants. Their findings were “unambiguously supportive” (2018: 504) of the link between empathy and helping behavior. Batson’s answer to this question is clear. Having reviewed the evidence from research designed to test the empathy-altruism hypothesis against the six egoistic alternatives …, it is time to come to a conclusion—albeit tentative—about the status of this hypothesis. The idea that empathy produces altruistic motivation may seem improbable given the dominance of Western thought by the doctrine of universal egoism. Yet, in the words of Sherlock Holmes, “When you have eliminated the impossible, whatever remains, however improbable , must be the truth”. It seems impossible for any known egoistic explanation of the empathy-helping relationship—or any combination of them—to account for the research evidence we have reviewed. So what remains? The empathy-altruism hypothesis. Pending new evidence or a plausible new egoistic explanation of the existing evidence, we seem forced to accept this improbable hypothesis as true. (Batson 2011: 160) [ 21 ] Batson’s research program is compelling, and he certainly has shown that the empathy-altruism hypothesis is “in the hunt”, but his findings are not conclusive. There are a number of reasonable challenges to the methodology and the conclusions in some of Batson’s studies. Setting these out in detail is a substantial project (see Stich, Doris, & Roedder 2010). But there is also a plausible egoistic hypothesis that has not been systematically explored. In recent years, a number of authors have made an impressive case for the hypothesis that belief in a “Big God”—a supernatural being who is omniscient, morally concerned, and acts as a policing agent in human affairs—played a crucial role in the transition from face-to-face “band level” human groups made up of at most a few hundred individuals to much larger tribal groups, and ultimately to chiefdoms and nation states (Norenzayan et al. 2016). These are provocative and controversial ideas. Much less controversial is the claim that many people believe that even when no other human can observe them, a supernatural being of some sort is aware of what they are doing and thinking, and that this being may punish thoughts and behavior it disapproves of and reward thoughts and behavior it approves of, with the punishments and rewards delivered either during the agent’s lifetime or after she dies. [ 22 ] In the experiments, described in section 5.1 , designed to test the empathy-altruism hypothesis against the social punishment hypothesis, Batson and his colleagues went to great lengths to insure that participants in the “low potential for negative social evaluation” condition would think that no one knew of their decisions, and thus that no one would think badly of them or sanction them if they decided not to help. But, of course, none of the steps taken to insure secrecy would be effective in keeping an omniscient God from knowing what these participants had decided. So if we assume that many people believe an omniscient God wants them to help others in need, and that they believe Divine sanctions for not helping are more likely when the target engenders empathy, [ 23 ] the experiments do nothing to rule out a variation of the social punishment hypothesis which maintains that participants are motivated by a desire to avoid punishments administered by God. The egoistic alternative just sketched, which might be called “the divine punishment hypothesis”, also leads to the pattern of predictions derived from the empathy-altruism hypothesis sketched in Table 5 , and the results reported in Table 6 . The bottom line is that using the Sherlock Holmes standard that Batson favors, there is still a lot of work to do. There is a family of egoistic hypotheses invoking beliefs in supernatural punishments—or supernatural rewards—that still needs to be ruled out before we accept the “improbable hypothesis” as true. [ 24 ] In the colorful passage quoted at the beginning of section 5.4 , Batson seems to suggest that in the debate between egoists and altruists there are only two possible outcomes. If all human behavior is ultimately motivated by self-interested desires, then the egoist wins; if some human behavior is motivated by ultimate desires for the well-being of other people, then the altruist wins. However, as noted in section 2 , the dialectical landscape is more complex, for there are many desires that are neither self-interested nor desires for the well-being of other people. If any of these are ultimate desires that lead to behavior, then the egoist is mistaken. But, as Batson clearly recognizes, this would not vindicate altruism; both egoism and altruism might be mistaken. Batson has used the term principlism for one family of ultimate desires that would support neither egoism nor altruism. Principlism is motivation with the ultimate goal of upholding some moral principle—for example, a principle of fairness or justice, or the utilitarian principle of greatest good for the greatest number. (Batson 2011: 220) Under some circumstances, one or another of these principles might require helping behavior, though that helping behavior would not be altruistic, since the ultimate desire motivating the behavior is to uphold the principle. On Batson’s view, we really don’t know much about principlism. To the best of my knowledge, there is no clear empirical evidence that upholding justice (or any other moral principle) functions as an ultimate goal. [ 25 ] Nor is there clear empirical evidence that rules this possibility out. (Batson 2011: 224) But if that’s right, then Batson’s conclusion that the empathy-altruism hypothesis is true and that people are sometimes altruistic is premature. For even if it were conceded that all the plausible egoistic alternatives to empathy-altruism have been excluded, the job of testing empathy-altruism against principalist alternatives has hardly begun. Moreover, the scope of that project may be much larger than Batson imagines. One way to see this is to ask which action guiding principles are moral principles. [ 26 ] There is ongoing debate about this question in both philosophy and psychology (Stich 2018). Though Batson does not address that debate, the examples he offers (“fairness or justice or the utilitarian principle”) suggest that when he talks about moral principles he has a rather limited set of principles in mind. But if principlism is limited to a relatively small set of moral principles familiar from the philosophical literature, then principlism hardly exhausts the non-egoistic alternatives that defenders of psychological altruism must rule out. In recent years, there has been a growing body of work on the role of norms in human life, where norms are understood as action guiding rules that can govern just about any human activity. Researchers from a variety of disciplines have argued that norms, and a robust innate psychology for acquiring, storing and acting on norms, have played a fundamental role in shaping human culture and making humans the most successful large animal on the planet (Henrich 2015; Boyd 2018; Kelly & Davis 2018). Others have proposed accounts of norm psychology on which people have ultimate desires to comply with culturally acquired norms (Sripada & Stich 2006) and accounts of how a psychological system generating such ultimate desires might be favored by natural selection (Sripada 2008). The sorts of behavioral rules that count as norms in this literature might well include the sorts of moral principles that Batson had in mind when he characterized principlism. But these are only a small subset of the norms that these researchers have in mind. What makes all of this relevant to our current topic is that any culturally acquired norm might generate an ultimate desire to comply, and most of those ultimate desires are neither egoistic nor altruistic. Thus to make a plausible case that an episode of helping behavior is altruistic, it is not enough to rule out egoistic explanations and explanations that appeal to principlism. The defender of psychological altruism must also rule out explanations that trace the helping behavior to an ultimate desire to comply with any of the vast collection of norms that prevail in human cultures. And that’s a job that defenders of altruism have not even begun. Another possibility is that some helping behavior might not be motivated by ultimate desires at all. Gęsiarz and Crockett (2015) argue that, in addition to the goal-directed system, behavior, including helping behavior, is sometimes produced by what they call the habitual and Pavlovian systems. The habitual system leads to actions that have the highest expected value based on previous life experiences rather than possible consequences indicated by features of the current situation. As a result, helping behavior may be repeated in the future and in circumstances in which motivating factors like the promise of rewards are absent if the behavior has been rewarded in the past. Like the habitual system, the Pavlovian system produces behavior with the highest expected value based on the past. Unlike the habitual system, however, the Pavlovian system produces behavior that has been successful in the evolutionary past, rather than in an individual’s past. This means that behavioral dispositions that have led to reproductive success in a individual’s evolutionary past may have become innate or “hard-wired” through natural selection. If it is indeed the case that some helping behavior is produced by the habitual or Pavlovian systems, then egoism is false. And if some helping behavior is egoistically motivated and the rest is produced by the habitual and Pavlovian systems, then altruism is also false. Batson and his collaborators have accomplished a great deal. They have formulated a sophisticated altruist hypothesis, the empathy-altruism hypothesis, that can be tested against competing egoist hypotheses, and they have designed experiments making a strong case that many of those egoist hypotheses are false. But to show that altruism is true, it is not enough to show that specific egoist hypotheses can’t explain specific episodes of helping behavior. Nor would it be enough to show that all plausible versions of egoism are false. It must also be shown that episodes of helping behavior that can’t be explained egoistically can’t be explained by another process, such as principalistic ultimate motivation or ultimate motivation by a non-moral norm. In addition, the defender of altruism must show that non-egoistic episodes of helping behavior are not the product of the habitual or Pavlovian systems. None of Batson’s experiments were designed to rule out these non-egoistic options or others that might be suggested. So there is still much work to be done. On a more positive note, it seems that Batson and his associates have shown quite conclusively that the methods of experimental psychology can move the debate forward. Indeed, one might argue that Batson has made more progress in this area during the last four decades than philosophers using the traditional philosophical methodology of a priori arguments buttressed by anecdote and intuition have made in the previous two millennia. Their work powerfully demonstrates the utility of empirical methods in moral psychology; philosophical moral psychologists debating the altruism-egoism question have always made empirical claim, and it is now evident that the human sciences possess resources to help us empirically assess those empirical claims. Aquinas, Thomas, 1270 [1917], The Summa Theologica , Vol 2, Part II, New York: Benziger Brothers. Aron, Arthur, Elaine N. Aron, and Danny Smollan, 1992, “Inclusion of Other in the Self Scale and the Structure of Interpersonal Closeness”, Journal of Personality and Social Psychology , 63(4): 596–612. doi:10.1037/0022-3514.63.4.596 Aron, Arthur, Elaine N. Aron, Michael Tudor, and Greg Nelson, 1991, “Close Relationships as Including Other in the Self”, Journal of Personality and Social Psychology , 60(2): 241–253. doi:10.1037/0022-3514.60.2.241 Aubrey, John, 1650–1695 [1949], Brief Lives , Oliver Lawson Dick (ed.), Boston: David R. Godine. Aubrey’s sketch of Hobbes is available online at https://mathshistory.st-andrews.ac.uk/Obituaries/Hobbes_Aubrey/ Badhwar, Neera Kapur, 1993, “Altruism Versus Self-Interest: Sometimes a False Dichotomy”, Social Philosophy and Policy , 10(1): 90–117. doi:10.1017/S0265052500004039 Batson, C. Daniel, 1991, The Altruism Question: Toward a Social-Psychological Answer , Hillsdale, NJ: Lawrence Erlbaum Associates. –––, 1998, “Altruism and Prosocial Behavior”, in Daniel T. Gilbert, Susan T. Fiske, and Gardner Lindzey (eds.), The Handbook of Social Psychology , volume 2, fourth edition, Boston: McGraw-Hill, pp. 282–316. –––, 2011, Altruism in Humans , Oxford: Oxford University Press. doi:10.1093/acprof:oso/9780195341065.001.0001 –––, 2012, “A History of Prosocial Behavior Research”, in Arie W. Kruglanski and Wolfgang Stroebe, (eds.), Handbook of the History of Social Psychology , New York: Psychology Press, pp. 243–264. doi:10.4324/9780203808498.ch12 –––, 2015, “Testing the Empathy-Altruism Hypothesis Against Egoistic Alternatives”, in Lorraine L. Besser-Jones and Michael Slote (eds.), The Routledge Companion to Virtue Ethics , New York: Routledge, pp. 385–400. Batson, C. Daniel, Bruce D. Duncan, Paula Ackerman, Terese Buckley, and Kimberly Birch, 1981, “Is Empathic Emotion a Source of Altruistic Motivation?” Journal of Personality and Social Psychology , 40(2): 290–302. doi:10.1037/0022-3514.40.2.290 Batson, C. Daniel, Patricia Schoenrade, and W. Larry Ventis, 1993. Religion and the Individual: A Social-Psychological Perspective , New York: Oxford University Press. Batson, C. Daniel, Karen O’Quin, Jim Fultz, Mary Vanderplas, and Alice M. Isen, 1983, “Influence of Self-Reported Distress and Empathy on Egoistic versus Altruistic Motivation to Help”, Journal of Personality and Social Psychology , 45(3): 706–718. doi:10.1037/0022-3514.45.3.706 Batson, C. Daniel, Karen Sager, Eric Garst, Misook Kang, Kostia Rubchinsky, and Karen Dawson, 1997, “Is Empathy-induced Helping Due to Self-other Merging?”, Journal of Personality and Social Psychology , 73(3): 495–509. doi:10.1037/0022-3514.73.3.495 Batson, C. Daniel, Kathryn C. Oleson, Joy L. Weeks, Sean P. Healy, Penny J. Reeves, Patrick Jennings, and Thomas Brown, 1989, “Religious Prosocial Motivation: Is It Altruistic or Egoistic?”, Journal of Personality and Social Psychology , 57(5): 873–884. doi:10.1037/0022-3514.57.5.873 Baumeister, Roy F., 1998, “The Self”, in The Handbook of Social Psychology , fourth edition, Daniel T. Gilbert, Susan T. Fiske, and Gardner Lindzey (eds.), Boston: McGraw-Hill, vol. 1, 680–740. Beatty, John, 1992, “Fitness: Theoretical Contexts”, in Keywords in Evolutionary Biology , Evelyn Fox Keller and Elisabeth A. Lloyd (eds.), Cambridge, MA: Harvard University Press. Boyd, Robert, 2018, A Different Kind of Animal: How Culture Transformed Our Species , Princeton, NJ: Princeton University Press. Broad, C.D., 1930, Five Types of Ethical Theory , New York: Harcourt, Brace. –––, 1950, “Egoism as a Theory of Human Motives”, The Hibbert Journal , 48: 105–114. Reprinted in his Ethics and the History of Philosophy: Selected Essays , London: Routledge and Kegan Paul, 1952, 218–231. Butler, Joseph, 1726 [1887], Human Nature and Other Sermons , Henry Morley (ed.), London: Cassell & Company, Limited, 1887. [ Butler 1726 [1887] available online ] Chambers, Chris, 2017, The Seven Deadly Sins of Psychology: A Manifesto for Reforming the Culture of Scientific Practice , Princeton, NJ: Princeton University Press. Cialdini, Robert B., Stephanie L. Brown, Brian P. Lewis, Carol Luce and Stephen L. Neuberg, 1997, “Reinterpreting the Empathy-Altruism Relationship: When One into One Equals Oneness”, Journal of Personality and Social Psychology , 73(3), 481– 494. doi:10.1037/0022-3514.73.3.481 Clavien, Christine and Rebekka A. Klein, 2010, “Eager for Fairness or for Revenge? Psychological Altruism in Economics”, Economics and Philosophy , 26(3): 267–290. doi:10.1017/S0266267110000374 Clavien, Christine and Michel Chapuisat, 2013, “Altruism across Disciplines: One Word, Multiple Meanings”, Biology & Philosophy , 28(1): 125–140. doi:10.1007/s10539-012-9317-3 De Waal, Frans B.M., 2008, “Putting the Altruism Back Into Altruism: The Evolution of Empathy”, Annual Review of Psychology , 59(1): 279–300. doi:10.1146/annurev.psych.59.103006.093625 Dixon, Thomas, 2008, The Invention of Altruism: Making Moral Meanings in Victorian Britain , Oxford: Oxford University Press. doi:10.5871/bacad/9780197264263.001.0001 Dovidio, John F., Judith Allen, and David A. Schroeder, 1990, “Specificity of Empathy-induced Helping: Evidence for Altruistic Motivation”, Journal of Personality and Social Psychology , 59(2): 249–60. doi:10.1037/0022-3514.59.2.249 Eisenberg, Nancy and Paul A. Miller, 1987, “The Relation of Empathy to Prosocial and Related Behaviors”, Psychological Bulletin , 101(1): 91–119. doi:10.1037/0033-2909.101.1.91 Feigin, Svetlana, Glynn Owens, and Felicity Goodyear-Smith, 2014, “Theories of Human Altruism: A Systematic Review”, Journal of Psychiatry and Brain Functions , 1: art. 5. doi:10.7243/2055-3447-1-5 Feinberg, Joel, 1965 [1999], “Psychological Egoism”, in Reason and Responsibility , Joel Feinberg (ed.), Belmont, CA: Dickenson Publishing. Reprinted in various editions including the tenth, co-edited with Russ Shafer-Landau, Belmont, CA: Wadsworth, 1999. Based on materials composed for philosophy students at Brown University, 1958. Frankena, William K., 1967, “The Concept of Morality”, in University of Colorado Studies: Series in Philosophy , 3, Boulder, CO: University of Colorado Press, 1–22. Reprinted in The Definition of Morality , Gerald Wallace and Arthur David McKinnon Walker (eds.), London: Methuen, 1970, 146–173. Fultz, Jim, C. Daniel Batson, Victoria A. Fortenbach, Patricia M. McCarthy, and Laurel L. Varney, 1986, “Social Evaluation and the Empathy-Altruism Hypothesis”, Journal of Personality and Social Psychology , 50(4): 761–769. doi:10.1037/0022-3514.50.4.761 Gęsiarz, Filip and Molly J. Crockett, 2015, “Goal-directed, Habitual and Pavlovian Prosocial Behavior”, Frontiers in Behavioral Neuroscience , 9: 135. doi:10.3389/fnbeh.2015.00135 Ghiselin, Michael, 1974, The Economy of Nature and the Evolution of Sex , Berkeley: University of California Press. Goldman, Alvin I., 1970, A Theory of Human Action , Englewood-Cliffs, NJ: Prentice-Hall. Grant, Colin, 1997, “Altruism: A Social Science Chameleon”, Zygon , 32(3): 321–40. doi:10.1111/0591-2385.00094/ Henrich, Joseph, 2015, The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter , Princeton, NJ: Princeton University Press. Hobbes, Thomas, 1651 [1981], Leviathan: Edited with an Introduction by C.B. Macpherson , London: Penguin Books. Hoffman, Martin L., 1991, “Is Empathy Altruistic?” Psychological Inquiry , 2(2): 131–133. doi:10.1207/s15327965pli0202_6 Hornstein, Harvey A., 1991, “Empathic Distress and Altruism: Still Inseparable”, Psychological Inquiry , 2, 133–135. doi:10.1207/s15327965pli0202_7 Joyce, Richard, 2006, The Evolution of Morality , Cambridge, MA: MIT Press. Kant, Immanuel, 1785 [1949], Fundamental Principles of the Metaphysics of Morals , translated by Thomas K. Abbott. Englewood Cliffs, NJ: Prentice Hall/Library of Liberal Arts. Kelly, Daniel and Taylor Davis, 2018, “Social Norms and Human Normative Psychology”, Social Philosophy and Policy , 35(1): 54–76. doi:10.1017/S0265052518000122 Kerr, Benjamin, Peter Godfrey-Smith, and Marcus W. Feldman, 2004, “What Is Altruism?”, Trends in Ecology & Evolution , 19(3): 135–140. doi:10.1016/j.tree.2003.10.004 Kihlstrom, John F. and Nancy Cantor, 1984, “Mental Representations of the Self”, in Advances in Experimental Social Psychology , volume 17, Leonard Berkowitz (ed.), New York: Academic Press. 1–47. doi:10.1016/S0065-2601(08)60117-3 Kitcher, Philip, 2010, “Varieties of Altruism”, Economics and Philosophy , 26(2): 121–148. doi:10.1017/S0266267110000167 –––, 2011, The Ethical Project , Cambridge, MA: Harvard University Press. Krebs, Dennis, 1975, “Empathy and Altruism”, Journal of Personality and Social Psychology , 32(6): 1134–1146. doi:10.1037/0022-3514.32.6.1134 LaFollette, Hugh, 2000a, “Introduction”, in LaFollette 2000b: 1–12. ––– (ed.), 2000b, The Blackwell Guide to Ethical Theory , Oxford: Blackwell Publishing. Lerner, Melvin J., 1980, The Belief in a Just World: A Fundamental Delusion . New York: Plenum. Ma, Vaunne and Thomas J. Schoeneman, 1997, “Individualism Versus Collectivism: A Comparison of Kenyan and American Self-Concepts”, Basic and Applied Social Psychology , 19(2): 261–273. doi:10.1207/s15324834basp1902_7 MacIntyre, Alasdair, 1967, “Egoism and Altruism”, in Paul Edwards (ed.), The Encyclopedia of Philosophy , vol. 2, first edition, New York: Macmillan, pp. 462–466. Markus, Hazel and Elissa Wurf, 1987, “The Dynamic Self-Concept: A Social Psychological Perspective”, Annual Review of Psychology , 38(1): 299–337. doi:10.1146/annurev.ps.38.020187.001503 Markus, Hazel R. and Shinobu Kitayama, 1991, “Culture and the Self: Implications for Cognition, Emotion, and Motivation”, Psychological Review , 98(2): 224–253. doi:10.1037/0033-295X.98.2.224 May, Joshua, 2011a, “Psychological Egoism”, Internet Encyclopedia of Philosophy , URL = < https://www.iep.utm.edu/psychego/ > –––, 2011b, “Egoism, Empathy, and Self-Other Merging”, Southern Journal of Philosophy , 49(s1): 25–39. doi:10.1111/j.2041-6962.2011.00055.x –––, 2011c, “Relational Desires and Empirical Evidence against Psychological Egoism: On Psychological Egoism”, European Journal of Philosophy , 19(1): 39–58. doi:10.1111/j.1468-0378.2009.00379.x McAuliffe, William H. B., Daniel E. Forster, Joachner Philippe, and Michael E. McCullough, 2018, “Digital Altruists: Resolving Key Questions about the Empathy–Altruism Hypothesis in an Internet Sample”, Emotion , 18(4): 493–506. doi:10.1037/emo0000375 Mill, John Stuart, 1861 [2011], Utilitarianism , first published as three articles in Fraser’s Magazine . Printed as a book London: Parker, Son & Bourn, 1863. Reprinted 2011, George Sher (ed.), Indianapolis, IN: Hackett. Nagel, Thomas, 1970, The Possibility of Altruism , Oxford: Clarendon Press. –––, 1986, The View From Nowhere , New York and Oxford: Oxford University Press. Norenzayan, Ara, Azim F. Shariff, Will M. Gervais, Aiyana K. Willard, Rita A. McNamara, Edward Slingerland, and Joseph Henrich, 2016, “The Cultural Evolution of Prosocial Religions”, Behavioral and Brain Sciences , 39: e1. doi:10.1017/S0140525X14001356 Piccinini, Gualtiero and Armin W. Schulz, 2019, “The Ways of Altruism”, Evolutionary Psychological Science , 5(1): 58–70. doi:10.1007/s40806-018-0167-3 Piliavin, Jane Allyn and Hong-Wen Charng, 1990, “Altruism: A Review of Recent Theory and Research”, Annual Review of Sociology , 16: 27–65. doi:10.1146/annurev.so.16.080190.000331 Purzycki, Benjamin Grant, Coren Apicella, Quentin D. Atkinson, Emma Cohen, Rita Anne McNamara, Aiyana K. Willard, Dimitris Xygalatas, Ara Norenzayan, and Joseph Henrich, 2016, “Moralistic Gods, Supernatural Punishment and the Expansion of Human Sociality”, Nature , 530(7590): 327–330. doi:10.1038/nature16980 Purzycki, Benjamin Grant, Joseph Henrich, Coren Apicella, Quentin D. Atkinson, Adam Baimel, Emma Cohen, Rita Anne McNamara, Aiyana K. Willard, Dimitris Xygalatas, and Ara Norenzayan, 2018, “The Evolution of Religion and Morality: A Synthesis of Ethnographic and Experimental Evidence from Eight Societies”, Religion, Brain & Behavior , 8(2): 101–132. doi:10.1080/2153599X.2016.1267027 Rachels, James, 2000, “Naturalism”, in LaFollette 2000b: 74–91. –––, 2003, The Elements of Moral Philosophy , fourth edition, New York: McGraw-Hill. Ramsey, Grant, 2006, “Block Fitness”, Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences , 37(3): 484–498. doi:10.1016/j.shpsc.2006.06.009 –––, 2016, “Can Altruism Be Unified?”, Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences , 56: 32–38. doi:10.1016/j.shpsc.2015.10.007 Ramsey, Grant and Robert Brandon, 2011, “Why Reciprocal Altruism Is Not a Kind of Group Selection”, Biology & Philosophy , 26(3): 385–400. doi:10.1007/s10539-011-9261-7 Schramme, Thomas, 2017, “Empathy and Altruism”, in The Routledge Handbook of Philosophy of Empathy . Heidi Maibom (ed.), New York: Routledge, 203–214. Schroeder, David A., Louis A. Penner, John F. Dovidio, and Jane A. Piliavin, 1995, The Psychology of Helping and Altruism: Problems and Puzzles , New York: McGraw-Hill. Schroeder, William, 2000, “Continental Ethics”, in LaFollette 2000b: 375–399. Schulz, Armin W., 2011, “Sober and Wilson’s Evolutionary Arguments for Psychological Altruism: A Reassessment”, Biology and Philosophy , 26(2): 251–260. doi:10.1007/s10539-009-9179-5 Shariff, Azim F. and Ara Norenzayan, 2007, “God is Watching You”, Pyschological Science , 18(9), 803–809. Shariff, Azim F., Aiyana K. Willard, Teresa Andersen, and Ara Norenzayan, 2016, “Religious Priming: A Meta-Analysis With a Focus on Prosociality”, Personality and Social Pyschology Review , 20(1):27–48. doi:10.1177/1088868314568811 Slote, Michael Anthony, 1964, “An Empirical Basis for Psychological Egoism”, Journal of Philosophy , 61(18): 530–537. doi:10.2307/2023495 –––, 2013, “Egoism and Emotion”, Philosophia , 41(2): 313–335. doi:10.1007/s11406-013-9434-5 Smith, Adam, 1759 [1853], The Theory of Moral Sentiments , London: Henry G. Bohn. Originally published 1759, Sober, Elliott and David Sloan Wilson, 1998, Unto Others: The Evolution and Psychology of Unselfish Behavior , Cambridge, MA: Harvard University Press. Sripada, Chandra Sekhar, 2008, “Adaptationism, Culture, and the Malleability of Human Nature”, in The Innate Mind, Volume 3: Foundations and the Future , Peter Carruthers, Stephen Laurence, and Stephen Stich (eds.), New York: Oxford University Press. doi:10.1093/acprof:oso/9780195332834.003.0016 Sripada, Chandra Sekhar and Stephen Stich, 2007, “A Framework for the Psychology of Norms”, in The Innate Mind: Volume 2: Culture and Cognition, Peter Carruthers , Stephen Laurence, and Stephen Stich (eds.), New York: Oxford University Press. doi:10.1093/acprof:oso/9780195310139.003.0017 Stich, Stephen, 2007, “Evolution, Altruism and Cognitive Architecture: A Critique of Sober and Wilson’s Argument for Psychological Altruism”, Biology and Philosophy , 22(2): 267–281. doi:10.1007/s10539-006-9030-1 –––, 2018, “The Quest for the Boundaries of Morality”, in The Routledge Handbook of Moral Epistemology , Aaron Zimmerman, Karen Jones, and Mark Timmons (eds.), New York: Routledge, 15–37. doi:10.4324/9781315719696-2 Stich, Stephen, John M. Doris, and Erica Roedder, 2010, “Altruism”, in The Moral Psychology Handbook , John M. Doris and The Moral Psychology Research Group (eds.)., Oxford: Oxford University Press, 147–205. Stich, Stephen and Tom Donaldson, 2018, Philosophy: Asking Questions—Seeking Answers , New York: Oxfrod University Press. Stocks, Eric L., David A. Lishner and Stephanie K. Decker, 2009, “Altruism or Psychological Escape: Why Does Empathy Promote Prosocial Behavior?” European Journal of Social Psychology , 39(5): 649–665. doi:10.1002/ejsp.561 Stotland, Ezra, 1969, “Exploratory Investigations of Empathy”, in Advances in Experimental Social Psychology , volume 4, Leonard Berkowitz (ed.), New York: Academic Press, 271–314. doi:10.1016/S0065-2601(08)60080-5 Toi, Miho and C. Daniel Batson, 1982, “More Evidence that Empathy is a Source of Altruistic Motivation”, Journal of Personality and Social Psychology , 43(2): 281–292. doi:10.1037/0022-3514.43.2.281 Warneken, Felix and Michael Tomasello, 2008, “Extrinsic Rewards Undermine Altruistic Tendencies in 20-Month-Olds”, Developmental Psychology , 44(6): 1785–1788. doi:10.1037/a0013860 Yilmaz, Onurcan and Hasan G. Bahçekapili, 2016, “Supernatural and Secular Monitors Promote Human Cooperation Only If They Remind of Punishment”, Evolution and Human Behavior , 37(1): 79–84. doi:10.1016/j.evolhumbehav.2015.09.005 How to cite this entry . Preview the PDF version of this entry at the Friends of the SEP Society . Look up topics and thinkers related to this entry at the Internet Philosophy Ontology Project (InPhO). Enhanced bibliography for this entry at PhilPapers , with links to its database. Moral Psychology Research Group Papers on Altruism and Psychological Egoism , at PhilPapers.org Papers on Evolution of Altruism at PhilPapers.org Papers on Empathy & Sympathy at PhilPapers.ord altruism | altruism: biological | Comte, Auguste | culture: and cognitive science | egoism | empathy | experimental moral philosophy | hedonism | personal identity: and ethics | social norms Acknowledgments This entry expands and updates the “Egoism and Altruism” section in Doris, Stich, Phillips and Walmsley, “Moral Psychology: Empirical Approaches”, The Stanford Encyclopedia of Philosophy (Winter 2017 Edition), Edward N. Zalta (ed.), URL = <https://plato.stanford.edu/archives/win2017/entries/moral-psych-emp/>. Some material in this entry is borrowed from Stich, Doris and Roedder (2010). For helpful suggestions, we are grateful to Mark Alfano, C. Daniel Batson, William J. FitzPatrick, Adam Lerner, Joshua May, Samir Okasha, Gualtiero Piccinini, Alejandro Rosas, Thomas Schramme, Armin Schulz, Elliott Sober, Kim Sterelny, Valerie Tiberius and David Sloan Wilson. Our thanks to Zhao Wang who helped assemble and check the references. Copyright © 2020 by John Doris < jmd378 @ cornell . edu > Stephen Stich < stich . steve @ gmail . com > Lachlan Walmsley < ldw917 @ gmail . com > Accessibility Support SEP Mirror sites. View this site from another server: Info about mirror sites The Stanford Encyclopedia of Philosophy is copyright © 2023 by The Metaphysics Research Lab , Department of Philosophy, Stanford University Library of Congress Catalog Data: ISSN 1095-5054 An official website of the United States government The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site. The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely. Publications Account settings My Bibliography Collections Citation manager Save citation to file Email citation, add to collections. Create a new collection Add to an existing collection Add to My Bibliography Your saved search, create a file for external citation management software, your rss feed. Search in PubMed Search in NLM Catalog Add to Search An examination of the tension reduction hypothesis: the relationship between anxiety and alcohol in college students Affiliation. 1 University of Akron. PMID: 2618848 DOI: 10.1016/0306-4603(89)90007-5 The Tension Reduction Theory posits that alcohol is consumed to achieve tension reduction. The drinking patterns of high anxiety college students differed from low anxiety college students. Eighty-one students completed the Trait scale of the State-Trait Anxiety Inventory and the Khavari Alcohol Test (KAT). Several indices of alcohol use derived from the KAT were used to assess patterns of alcohol use. Five two-way analyses of variance were conducted using gender and anxiety as factors. Hypothesis One predicted that there would be a significant difference in alcohol consumption between high and low anxiety students when a comprehensive measure of alcohol use was used. This hypothesis was supported. Hypothesis Two predicted that frequency alone would not differentiate between anxiety levels; this was also supported. The Third Hypothesis was that volume measures of beer, wine and liquor would differentiate between the high and low anxiety levels; this hypothesis was partially supported--beer volume did differentiate between groups, while wine and liquor volume did not. The final hypothesis was that there would be an interaction between gender and anxiety; this was not supported. PubMed Disclaimer Similar articles Alcohol expectancies and social anxiety in male and female undergraduates. O'Hare TM. O'Hare TM. Addict Behav. 1990;15(6):561-6. doi: 10.1016/0306-4603(90)90057-5. Addict Behav. 1990. PMID: 2075853 Anxiety and drinking behavior: moderating effects of tension-reduction alcohol outcome expectancies. Kushner MG, Sher KJ, Wood MD, Wood PK. Kushner MG, et al. Alcohol Clin Exp Res. 1994 Aug;18(4):852-60. doi: 10.1111/j.1530-0277.1994.tb00050.x. Alcohol Clin Exp Res. 1994. PMID: 7978095 Ego identity status and reported alcohol consumption: a study of first-year college students. Bishop DI, Macy-Lewis JA, Schnekloth CA, Puswella S, Struessel GL. Bishop DI, et al. J Adolesc. 1997 Apr;20(2):209-18. doi: 10.1006/jado.1996.0078. J Adolesc. 1997. PMID: 9104656 Stress and alcohol interaction: an update of human research. Pohorecky LA. Pohorecky LA. 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Dvorak RD, Kuvaas NJ, Lamis DA, Pearson MR, Stevenson BL. Dvorak RD, et al. J Drug Educ. 2015;45(3-4):156-84. doi: 10.1177/0047237916639030. J Drug Educ. 2015. PMID: 27075609 Free PMC article. Ecological momentary assessment of acute alcohol use disorder symptoms: associations with mood, motives, and use on planned drinking days. Dvorak RD, Pearson MR, Day AM. Dvorak RD, et al. Exp Clin Psychopharmacol. 2014 Aug;22(4):285-97. doi: 10.1037/a0037157. Epub 2014 Jun 16. Exp Clin Psychopharmacol. 2014. PMID: 24932896 Free PMC article. Search in MeSH LinkOut - more resources Full text sources. Elsevier Science MedlinePlus Consumer Health Information MedlinePlus Health Information Citation Manager NCBI Literature Resources MeSH PMC Bookshelf Disclaimer The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Unauthorized use of these marks is strictly prohibited. 274 IMAGES Reduction Explaination of Reduction, definitons,Types PPT Hypothesis reduction and solution synthesis. The drive reduction hypothesis 13 Different Types of Hypothesis (2024) VIDEO What Is A Hypothesis? Reductionism proofs exist only in mathematics Hypothesis Testing 9.1.1 Define Oxidation and Reduction in Terms of Electron Loss and Gain v2 IB Chemistry Reduction (mathematics) COMMENTS Scientific Reduction Scientific Reduction. First published Tue Apr 8, 2014; substantive revision Wed Mar 6, 2024. The English verb 'reduce' derives from the Latin ' reducere ', whose literal meaning 'to bring back', informs its metaphorical use in philosophy. If one asserts that the mental reduces to the physical, that heat reduces to kinetic molecular ... Reductionism The definition of 'reduction' that Kemeny and Oppenheim defend says that: A theory T is reduced to another theory B relative to a set of observational data O if: ... in Paul Oppenheim and Hilary Putnam's paper "Unity of Science as a Working Hypothesis," this model of reduction is employed in the context of a larger metaphysical scheme ... Origin of Viruses The progressive, or escape, hypothesis states that viruses arose from genetic elements that gained the ability to move between cells; 2. the regressive, or reduction, hypothesis asserts that ... Reductionism Theory reduction itself is divisible into three parts: translation, derivation, and explanation. [4] ... what John Polkinghorne terms 'conceptual' or 'epistemological' reductionism [5] is the definition provided by Simon Blackburn [10] ... the continuum hypothesis is undecidable in the Zermelo-Fraenkel set theory as shown by Cohen. In science Reductionism in Biology Reductionism encompasses a set of ontological, epistemological, and methodological claims about the relations between different scientific domains. The basic question of reduction is whether the properties, concepts, explanations, or methods from one scientific domain (typically at higher levels of organization) can be deduced from or explained ... What is the Point of Reduction in Science? The numerous and diverse roles of theory reduction in science have been insufficiently explored in the philosophy literature on reduction. Part of the reason for this has been a lack of attention paid to reduction 2 (successional reduction)—although I here argue that this sense of reduction is closer to reduction 1 (explanatory reduction) than is commonly recognised, and I use an account of ... Delay reduction hypothesis Delay reduction hypothesis. In operant conditioning, the delay reduction hypothesis (DRH; also known as delay reduction theory) is a quantitative description of how choice among concurrently available chained schedules of reinforcement is allocated. The hypothesis states that the greater improvement in temporal proximity to reinforcement (delay ... Reduction hypothesis The reduction hypothesis is a concept in biology suggesting that the complexity of viruses can be explained by a process of simplification or loss of genetic material over time. This idea connects to the evolutionary history of viruses, positing that their current forms result from the gradual reduction of their genomes, leading to a more streamlined and efficient replication strategy. Hypothesis Testing Present the findings in your results and discussion section. Though the specific details might vary, the procedure you will use when testing a hypothesis will always follow some version of these steps. Table of contents. Step 1: State your null and alternate hypothesis. Step 2: Collect data. Step 3: Perform a statistical test. On the scope of scientific hypotheses 2. The scientific hypothesis. In this section, we will describe a functional and descriptive role regarding how scientists use hypotheses. Jeong & Kwon [] investigated and summarized the different uses the concept of 'hypothesis' had in philosophical and scientific texts.They identified five meanings: assumption, tentative explanation, tentative cause, tentative law, and prediction. Delay Reduction Theory: Choice, Value, and Conditioned Reinforcement According to delay reduction theory (DRT), the conditioned reinforcing strength of a stimulus may be predicted by calculating the reduction in the duration of time to primary reinforcement signaled by that stimulus (Fantino, 1969; 1981; Squires & Fantino, 1971). The simplest form of DRT (from Fantino, 1981) states that: where tA is the time ... Being Reduced: New Essays on Reduction, Explanation, and Causation A second notion of "reduction" finds its locus classicus in Oppenheim and Putnam's (1958) "Unity of Science as a Working Hypothesis". This type of reduction, which Oppenheim and Putnam called a micro-reduction, is not semantic in character. Rather, it is a form of explanation in which the properties of a complex object can be "reduced", in the ... Drive-Reduction Theory of Motivation In Psychology Impact On Motivation. Drive reduction thosry is a theory of learning in which the goal of motivated behavior is a reduction of a drive state. The theory assumes that all motivated behavior arises from drives, stemming from a disruption in homeostasis, and that responses that lead to reduction of those drives tend to be reinforced or strengthened. Scientific Reduction Scientific Reduction. First published Tue Apr 8, 2014. The English verb 'reduce', derives from the Latin ' reducere ', whose literal meaning 'to bring back', informs its metaphorical use in philosophy. If one asserts that the mental reduces to the physical, that heat reduces to kinetic molecular energy, or that one theory reduces to ... Hypothesis Testing The Four Steps in Hypothesis Testing. STEP 1: State the appropriate null and alternative hypotheses, Ho and Ha. STEP 2: Obtain a random sample, collect relevant data, and check whether the data meet the conditions under which the test can be used. If the conditions are met, summarize the data using a test statistic. Hypothesis Testing: 4 Steps and Example Hypothesis testing is the process that an analyst uses to test a statistical hypothesis. The methodology depends on the nature of the data used and the reason for the analysis. Uncertainty reduction theory Uncertainty reduction theory. The uncertainty reduction theory, also known as initial interaction theory, developed in 1975 by Charles Berger and Richard Calabrese, is a communication theory from the post-positivist tradition. It is one of the few communication theories that specifically looks into the initial interaction between people prior ... Definition and Reduction Finally, I show how the concept of reduction sentences confuses in several ways the concepts of criterion and meaning analysis—although not in quite the same way as explicit definitions do. Type. Research Article. Information. Philosophy of Science , Volume 28 , Issue 4 , October 1961 , pp. 390 - 405. Drive Reduction Theory and Human Behavior The drive reduction theory of motivation became popular during the 1940s and 1950s as a way to explain behavior, learning, and motivation. The theory was created by behaviorist Clark Hull and further developed by his collaborator Kenneth Spence. According to the theory, the reduction of drives is the primary force behind motivation. Reductionism in Biology Reductionism encompasses a set of ontological, epistemological, and methodological claims about the relation of different scientific domains. The basic question of reduction is whether the properties, concepts, explanations, or methods from one scientific domain (typically at higher levels of organization) can be deduced from or explained by the properties, concepts, explanations, or methods ... The Tension Reduction Hypothesis revisited: an alcohol expectancy Conger'-^ first proposed the tension reduction hypothesis which in its simplest form "states that alcohol serves to reduce tension or anxiety, possibly because of the depressing or tranquillizing effects of alcohol on the nervous system. Drinking is thus reinforced by the tension reduction effects ob-tained"' (p. 175). Empirical Approaches to Altruism Indeed, many thinkers define the basic goal of morality as "selflessness" or "altruism". (W. Schroeder 2000: 396) ... Another popular egoistic strategy for explaining the link between empathy and helping behavior is the aversive-arousal reduction hypothesis, which maintains that witnessing someone in need, and the empathy it evokes, ... An examination of the tension reduction hypothesis: the ... The Tension Reduction Theory posits that alcohol is consumed to achieve tension reduction. The drinking patterns of high anxiety college students differed from low anxiety college students. ... Hypothesis One predicted that there would be a significant difference in alcohol consumption between high and low anxiety students when a comprehensive ... assignment essay homework paper phd report resume review speech thesis