logic Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises ...

, anti-psychologism (also logical objectivism or logical realism) is a

theory A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be s ...

about the nature of

logical truth Logical truth is one of the most fundamental concepts in logic. Broadly speaking, a logical truth is a statement which is true regardless of the truth or falsity of its constituent propositions. In other words, a logical truth is a statement whic ...

, 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 Immanuel Kant (, , ; 22 April 1724 – 12 February 1804) was a German philosopher and one of the central Enlightenment thinkers. Born in Königsberg, Kant's comprehensive and systematic works in epistemology, metaphysics, ethics, and ...

and

Bernard Bolzano Bernard Bolzano (, ; ; ; born Bernardus Placidus Johann Gonzal Nepomuk Bolzano; 5 October 1781 – 18 December 1848) was a Bohemian mathematician, logician, philosopher, theologian and Catholic priest of Italian extraction, also known for his liber ...

. The concept of logical objectivism or anti-psychologism was further developed by

Johannes Rehmke Johannes Rehmke (1 February 1848 – 23 December 1930) was a German philosopher and since 1885 professor at Greifswald University, later also provost of this university. He offered sharp criticisms of Immanuel Kant's approach to epistemology. In h ...

(founder of Greifswald objectivism) and

Gottlob Frege Friedrich Ludwig Gottlob Frege (; ; 8 November 1848 – 26 July 1925) was a German philosopher, logician, and mathematician. He was a mathematics professor at the University of Jena, and is understood by many to be the father of analytic phil ...

(founder of

logicism In the philosophy of mathematics, logicism is a programme comprising one or more of the theses that — for some coherent meaning of 'logic' — mathematics is an extension of logic, some or all of mathematics is reducible to logic, or some or all ...

the most famous anti-psychologist in the

philosophy of mathematics The philosophy of mathematics is the branch of philosophy that studies the assumptions, foundations, and implications of mathematics. It aims to understand the nature and methods of mathematics, and find out the place of mathematics in people's ...

), and has been the centre of an important debate in early

phenomenology Phenomenology may refer to: Art * Phenomenology (architecture), based on the experience of building materials and their sensory properties Philosophy * Phenomenology (philosophy), a branch of philosophy which studies subjective experiences and a ...

and

analytical philosophy Analytic philosophy is a branch and tradition of philosophy using analysis, popular in the Western world and particularly the Anglosphere, which began around the turn of the 20th century in the contemporary era in the United Kingdom, United Sta ...

. Frege's work was influenced by Bolzano. Elements of anti-psychologism in the historiography of philosophy can be found in the work of the members of the 1830s speculative theist movement and the late work of

Hermann Lotze Rudolf Hermann Lotze (; ; 21 May 1817 – 1 July 1881) was a German philosopher and logician. He also had a medical degree and was well versed in biology. He argued that if the physical world is governed by mechanical laws and relations, then de ...

. The psychologism dispute (german: Psychologismusstreit) in 19th-century German-speaking philosophy is closely related to the contemporary

internalism and externalism Internalism and externalism are two opposite ways of integration of explaining various subjects in several areas of philosophy. These include human motivation, knowledge, justification, meaning, and truth. The distinction arises in many areas of d ...

debate in

epistemology Epistemology (; ), or the theory of knowledge, is the branch of philosophy concerned with knowledge. Epistemology is considered a major subfield of philosophy, along with other major subfields such as ethics, logic, and metaphysics. Episte ...

;

psychologism Psychologism is a family of philosophical positions, according to which certain psychological facts, laws, or entities play a central role in grounding or explaining certain non-psychological facts, laws, or entities. The word was coined by Johann ...

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). Psychologism was defended by

Theodor Lipps Theodor Lipps (; 28 July 1851 – 17 October 1914) was a Germans, German philosopher, famed for his theory regarding aesthetics, creating the framework for the concept of ''Einfühlung'' (empathy)'','' defined as, "projecting oneself onto the ob ...

Gerardus Heymans Gerardus Heymans (17 April 1857, Ferwert – 18 February 1930, Groningen) was a Dutch philosopher and psychologist.Hubbeling, H. G. (2013). Gerardus Heijmans (1857-1930). In ''Biografisch Woordenboek van Nederland.'' https://resources.huyge ...

Wilhelm Wundt Wilhelm Maximilian Wundt (; ; 16 August 1832 – 31 August 1920) was a German physiologist, philosopher, and professor, known today as one of the fathers of modern psychology. Wundt, who distinguished psychology as a science from philosophy and ...

Wilhelm Jerusalem Wilhelm Jerusalem (11 October 1854 in Dřenice – 15 July 1923 in Vienna) was an Austrian Jewish philosopher and pedagogue. Biography Jerusalem studied classical philosophy at the University of Prague and prepared a doctorate entitled "The I ...

Christoph von Sigwart Christoph von Sigwart (28 March 1830 – 4 August 1904) was a German philosopher and logician. He was the son of philosopher Heinrich Christoph Wilhelm Sigwart (31 August 1789 – 16 November 1844). Life After a course of philosophy ...

Theodor Elsenhans Theodor Elsenhans (1862-1918) was a German psychologist and neo-Kantian philosopher. Life Elsenhans started studying theology at the University of Tübingen, but became interested in philosophy. He received his doctorate in 1885. In 1902 he comple ...

, and

Benno Erdmann Benno Erdmann (30 May 1851, Guhrau – 7 January 1921, Berlin) was a German neo-Kantian philosopher, logician, psychologist and scholar of Immanuel Kant. Biography Erdmann received his Ph.D. in 1873 from the University of Berlin with a dis ...

Edmund Husserl , thesis1_title = Beiträge zur Variationsrechnung (Contributions to the Calculus of Variations) , thesis1_url = https://fedora.phaidra.univie.ac.at/fedora/get/o:58535/bdef:Book/view , thesis1_year = 1883 , thesis2_title ...

was another important proponent of anti-psychologism, and this trait passed on to other phenomenologists, such as

Martin Heidegger Martin Heidegger (; ; 26 September 188926 May 1976) was a German philosopher who is best known for contributions to phenomenology, hermeneutics, and existentialism. He is among the most important and influential philosophers of the 20th centur ...

, 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 Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premise ...

to "It is thought that 'no-p is a not-p'", psychologism does not logically stand.

Charles Sanders Peirce Charles Sanders Peirce ( ; September 10, 1839 – April 19, 1914) was an American philosopher, logician, mathematician and scientist who is sometimes known as "the father of pragmatism". Educated as a chemist and employed as a scientist for t ...

—whose fields included logic, philosophy, and experimental psychology—could also be considered a critic of psychologism in logic.

The return of psychologism

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 Dov M. Gabbay (; born October 23, 1945) is an Israeli logician. He is Augustus De Morgan Professor Emeritus of Logic at the Group of Logic, Language and Computation, Department of Computer Science, King's College London. Work Gabbay has auth ...

and John Woods, who concluded that "whereas mathematical logic must eschew psychologism, the new logic cannot do without it". See also:

Notes

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Overview

The return of psychologism

Notes

Further reading