In logic, anti-psychologism (also logical objectivism[1] or logical realism[2][3]) is a theory about the nature of logical truth, that it does not depend upon the contents of human ideas but exists independent of human ideas.

Overview

The anti-psychologistic treatment of logic originated in the works of Immanuel Kant and Bernard Bolzano.[4]

The concept of logical objectivism or anti-psychologism was further developed by Johannes Rehmke (founder of Greifswald objectivism)[5] and Gottlob Frege (founder of logicism the most famous anti-psychologist in the philosophy of mathematics), and has been the center of an important debate in early phenomenology and analytical philosophy. Frege's work was influenced by Bolzano.[6]

Elements of anti-psychologism in the historiography of philosophy can be found in the work of the members of the 1830s speculative theist movement[7] and the late work of Hermann Lotze.[8]

The psychologism dispute (German: Psychologismusstreit)[9] in 19th-century German-speaking philosophy is closely related to the contemporary internalism and externalism debate in epistemology; psychologism is often construed as a kind of internalism (the thesis that no fact about the world can provide reasons for action independently of desires and beliefs) and anti-psychologism as a kind of externalism (the thesis that reasons are to be identified with objective features of the world).[10]

Psychologism was defended by Theodor Lipps, Gerardus Heymans, Wilhelm Wundt, Wilhelm Jerusalem, Christoph von Sigwart, Theodor Elsenhans, and Benno Erdmann.[11]

Edmund Husserl was another important proponent of anti-psychologism, and this trait passed on to other phenomenologists, such as Martin Heidegger, whose doctoral thesis was meant to be a refutation of psychologism. They shared the argument that, because the proposition "no-p is a not-p" is not logically equivalent to "It is thought that 'no-p is a not-p'", psychologism does not logically stand.

Charles Sanders Peirce—whose fields included logic, philosophy, and experimental psychology[12]—could also be considered a critic of psychologism in logic.[13]

The return of psychologism

See also: Cognitive science and Naturalized epistemology

Psychologism is not widely held amongst logicians today, but something like it has some high-profile defenders especially among those who do research at the intersection of logic and cognitive science, for example Dov Gabbay and John Woods, who concluded that "whereas mathematical logic must eschew psychologism, the new logic cannot do without it".[14]

Notes

  1. ^ Dermot Moran, Rodney K. B. Parker (eds.), Studia Phaenomenologica: Vol. XV / 2015 – Early Phenomenology, Zeta Books, 2016, p. 75: "Husserl was an exponent of logical objectivism and an opponent of logical psychologism".
  2. ^ Edgar Morscher [de] (1972), "Von Bolzano zu Meinong: Zur Geschichte des logischen Realismus." In: Rudolf Haller (ed.), Jenseits von Sein und Nichtsein: Beiträge zur Meinong-Forschung, Graz, pp. 69–102.
  3. ^ Penelope Rush, "Logical Realism", in: Penelope Rush (ed.), The Metaphysics of Logic, Cambridge University Press, 2014, pp. 13–31.
  4. ^ Bernard Bolzano (Stanford Encyclopedia of Philosophy); Routledge Encyclopedia of Philosophy (1998): "Ryle, Gilbert (1900-76)."
  5. ^ Nikolay Milkov, Early Analytic Philosophy and the German Philosophical Tradition, London: Bloomsbury, 2020, p. 157.
  6. ^ Sundholm, B. G., "When, and why, did Frege read Bolzano?", LOGICA Yearbook 1999, 164–174 (2000).
  7. ^ William R. Woodward, Hermann Lotze: An Intellectual Biography, Cambridge University Press, 2015, pp. 74–5.
  8. ^ Sullivan, David. "Hermann Lotze". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
  9. ^ Matthias Rath, Der Psychologismusstreit in der deutschen Philosophie, 1994
  10. ^ Giuseppina D'Oro, "Collingwood, psychologism and internalism," European Journal of Philosophy 12(2):163–177 (2004): "internalism is often associated with psychologism".
  11. ^ Psychologism (Stanford Encyclopedia of Philosophy): "Examples of Psychologistic Reasoning"
  12. ^ Peirce (sometimes with Joseph Jastrow) investigated the probability judgments of experimental subjects, pioneering decision analysis. He and Jastrow wrote "On Small Differences in Sensation", Memoirs of the National Academy of Sciences (1885), 3, 73–83, presented 17 October 1884, reprinted in Collected Papers v. 7, paragraphs 21–35. Classics in the History of Psychology. Eprint.
  13. ^ Peirce attacked the idea, held by some logicians at that time, that rationality rests on a feeling of logicality, rather than on fact. See the first of Peirce's 1903 Lowell Institute Lectures "What Makes a Reasoning Sound?", Essential Peirce v. 2, pp. 242–257. See also the portion of Peirce's 1902 Minute Logic published in Collected Papers v. 2 (1931), paragraphs 18–19 and 39–43. Peirce held that mathematical and philosophical logics precede psychology as a special science and that they do not depend on it for principles.
  14. ^ Gabbay, Dov M.; Woods, John (March 2001). "The New Logic" (PDF). Logic Journal of the IGPL. 9 (2): 141–174. CiteSeerX 10.1.1.5.9046. doi:10.1093/jigpal/9.2.141. Archived from the original (PDF) on 2005-05-16. See also: Gabbay, Dov M.; Woods, John (2005) [2003]. A Practical Logic of Cognitive Systems. Amsterdam; Boston: North-Holland. doi:10.1016/s1874-5075(03)x8001-8. ISBN 044451385X. OCLC 52127672.

Further reading

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