The unity of science is a thesis in philosophy of science that says that all the sciences form a unified whole. The variants of the thesis can be classified as ontological (giving a unified account of the structure of reality) and/or as epistemic/pragmatic (giving a unified account of how the activities and products of science work). There are also philosophers who emphasize the disunity of science, which does not necessarily imply that there could be no unity in some sense but does emphasize pluralism in the ontology and/or practice of science.
Early versions of the unity of science thesis can be found in ancient Greek philosophers such as Aristotle, and in the later history of Western philosophy. For example, in the first half of the 20th century the thesis was associated with the unity of science movement led by Otto Neurath, and in the second half of the century the thesis was advocated by Ludwig von Bertalanffy in "General System Theory: A New Approach to Unity of Science" (1951) and by Paul Oppenheim and Hilary Putnam in "Unity of Science as a Working Hypothesis" (1958). It has been opposed by Jerry Fodor in "Special Sciences (Or: The Disunity of Science as a Working Hypothesis)" (1974), by Paul Feyerabend in Against Method (1975) and later works, and by John Dupré in "The Disunity of Science" (1983) and The Disorder of Things: Metaphysical Foundations of the Disunity of Science (1993).
Jean Piaget suggested, in his 1918 book Recherche and later books, that the unity of science can be considered in terms of a circle of the sciences, where logic is the foundation for mathematics, which is the foundation for mechanics and physics, and physics is the foundation for chemistry, which is the foundation for biology, which is the foundation for sociology, the moral sciences, psychology, and the theory of knowledge, and the theory of knowledge forms a basis for logic, completing the circle, without implying that any science could be reduced to any other.
- Bertalanffy, Ludwig von (December 1951). "General system theory: a new approach to unity of science: 1. Problems of general system theory". Human Biology. 23 (4): 302–312. JSTOR 41448003. PMID 14907026. Bertallanfy's article was part of a section that also included, in response, Carl G. Hempel's "General system theory and the unity of science" (pp. 313–322), Robert E. Bass's "Unity of nature" (pp. 323–327), and Hans Jonas's "Comment on general system theory" (pp. 328–335).
- Boyd, Richard; Gasper, Philip; Trout, J. D., eds. (1991). The philosophy of science. A Bradford book. Cambridge, MA: MIT Press. ISBN 0262023156. OCLC 22597466.
- Braun, Claude M. J.; Baribeau, Jacinthe M. C. (Summer 1984). "The classification of psychology among the sciences from Francis Bacon to Boniface Kedrov". Journal of Mind and Behavior. 5 (3): 245–259 (252–254). JSTOR 43853037.
- Cat, Jordi (2017). "The unity of science". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy (Fall 2017 ed.).
- Dupré, John (July 1983). "The disunity of science". Mind. 92 (367): 321–346. doi:10.1093/mind/XCII.367.321. JSTOR 2253810.
- Dupré, John (1993). The disorder of things: metaphysical foundations of the disunity of science. Cambridge, MA: Harvard University Press. ISBN 0674212606. OCLC 25746325.
- Feyerabend, Paul (1993) . Against method (3rd ed.). London; New York: Verso. ISBN 086091481X. OCLC 29026104.
- Feyerabend, Paul (2011). "The disunity of science". The tyranny of science. Cambridge, UK; Malden, MA: Polity Press. pp. 32–63. ISBN 978-0745651897. OCLC 668946683.
- Fodor, Jerry A. (October 1974). "Special sciences (or: The disunity of science as a working hypothesis)". Synthese. 28 (2): 97–115. doi:10.1007/BF00485230. JSTOR 20114958. S2CID 46979938. Reprinted in Boyd, Gasper & Trout 1991.
- Kitchener, Richard F. (September 1981). "The nature and scope of genetic epistemology". Philosophy of Science. 48 (3): 400–415 (413). doi:10.1086/289007. JSTOR 186987. S2CID 144785292.
Nowhere does Piaget suggest that sociology can be reduced to psychology, but instead refers to 'psycho-sociology'.
- Oppenheim, Paul; Putnam, Hilary (1958). "Unity of science as a working hypothesis". In Feigl, Herbert (ed.). Concepts, theories and the mind–body problem. Minnesota studies in the philosophy of science. Vol. 2. Minneapolis: University of Minnesota Press. pp. 3–36. hdl:11299/184622. ISBN 9780816601585. OCLC 2669746. Reprinted in Boyd, Gasper & Trout 1991.
- Piaget, Jean (1918). Recherche (PDF) (in French). Lausanne: Édition La Concorde. p. 59. OCLC 2565864. Archived (PDF) from the original on 2016-06-29. Retrieved 9 February 2017.
- Symons, John; Pombo, Olga; Torres, Juan Manuel, eds. (2011). Otto Neurath and the unity of science. Logic, epistemology, and the unity of science. Vol. 18. Dordrecht; New York: Springer-Verlag. doi:10.1007/978-94-007-0143-4. ISBN 9789400701427. OCLC 723045353.
- Tahko, Tuomas E. (2021). Unity of science. Cambridge elements in the philosophy of science. Cambridge, UK; New York: Cambridge University Press. doi:10.1017/9781108581417. ISBN 9781108713382. OCLC 1204142197.
- Wilson, Malcolm (2000). Aristotle's theory of the unity of science. Phoenix, supplementary volume. Vol. 38. Toronto: University of Toronto Press. doi:10.3138/9781442670990. ISBN 0802047963. OCLC 43634904.
- Bunge, Mario (2003). Emergence and convergence: qualitative novelty and the unity of knowledge. Toronto studies in philosophy. Toronto: University of Toronto Press. doi:10.3138/9781442674356. ISBN 0802088600. OCLC 52411064.
- Galison, Peter; Stump, David J., eds. (1996). The disunity of science: boundaries, contexts, and power. Writing science. Stanford, CA: Stanford University Press. ISBN 0804724369. OCLC 32468580.
- Kincaid, Harold (1997). Individualism and the unity of science: essays on reduction, explanation, and the special sciences. Worldly philosophy. Lanham, MD: Rowman & Littlefield. ISBN 0847686620. OCLC 36817265.
- Odum, Howard T. (1995). "Energy systems and the unification of science". In Hall, Charles A. S. (ed.). Maximum power: the ideas and applications of H.T. Odum. Niwot, CO: University Press of Colorado. pp. 365–372. ISBN 0870813625. OCLC 31436211.
- Pombo, Olga; Torres, Juan Manuel; Symons, John; Rahman, Shahid, eds. (2012). Special sciences and the unity of science. Dordrecht; New York: Springer-Verlag. doi:10.1007/978-94-007-2030-5. ISBN 9789400720299.
- Potochnik, Angela (May 2011). "A Neurathian conception of the unity of science" (PDF). Erkenntnis. 74 (3): 305–319. doi:10.1007/s10670-010-9228-0. JSTOR 41476691. S2CID 143918932.
- Ruphy, Stéphanie (2016) . Scientific pluralism reconsidered: a new approach to the (dis)unity of science. Pittsburgh: University of Pittsburgh Press. ISBN 9780822944584. OCLC 951158157.
- Unity of Science at PhilPapers
- Guide to the Unity of Science Movement Records 1934–1968 at the University of Chicago Special Collections Research Center