Psychologism is a philosophical position that attempts to reduce diverse forms of knowledge including concepts and principles of logic and mathematics to states of mind or phenomena that occur in the mind. It takes psychology as the fundamental discipline that can explain and justify knowledge in philosophy. Studies of the mind had been a part of philosophy since antiquity. Modern philosophers such as Descartes, Locke, Hume, and Kant made considerable contributions to the studies of the mind. In the nineteenth century, psychology became an independent discipline and flourished. Along with developments in psychology, some took psychology as the fundamental discipline upon which all other forms of knowledge are built and receive their justification. Psychologism is a form of reductionism that attempts to reduce other forms of knowledge including those of logic and mathematics into psychological concepts. In particular, psychologism challenges the idea of a priori knowledge of principles and concepts in logic and mathematics.


Frege delivered severe criticisms against psychologism on the ground that principles of logic are universally true a priori, and therefore are irreducible to psychological concepts. Upon receiving Frege’s criticism, Husserl gave up his earlier position based on psychologism, and become one of the major opponents of psychologism.

Historical background

Studies of the mind had traditionally been included as subjects of philosophy since antiquity. Modern philosophers such as Descartes, Locke, Hume, Kant, and others made considerable contributions to the studies of mind within their own philosophical frameworks. The natural sciences, which had been natural philosophy, gradually developed as independent disciplines. Late in the nineteenth century, empirical studies of the mind, such as experimental psychology, became solid independent disciplines. Wilhelm Wundt, Hermann Ebbinghaus, Franz Brentano, Carl Stumpf, Theodor Lipps, and others contributed to the development of psychology and philosophy. Franz Brentano in particular directly impacted Husserl. The early stages of Husserl's philosophy were formulated based on Brentano's ideas.

It was generally understood that the term psychologism was first used by J. E. Erdmann, a Hegelian, when he criticized the position of Friedrich Eduard Beneke in 1866. Beneke and Jakob Friedrich Fries (1773-1843) made a psychological interpretation of Kantian philosophy, and incorporated ideas from empiricism, particularly from Locke. They argued that psychology was the fundamental discipline upon which all philosophical disciplines such as logic, ethics, metaphysics, and others are built. Therefore, principles of logic and mathematics are reducible to psychological phenomena. Hegelians criticized their position as a superficial reading of Kant.

Beneke and Fries refused speculative metaphysics of German idealism and took a positivist approach in philosophy. They held that introspection of mental phenomena can explain philosophical knowledge including logic.

Frege’s Criticism

John Stuart Mill argued in his System of Logic that propositions in mathematics are generalizations of certain experiences. Empiricists argued that mathematical concepts do not exist independently and are derived by induction from human experience. The concept of numbers, for example, is generated by the act of counting. Philosophers of psychologism held to the idea of the psychological origin of mathematical concepts. Frege, in his Grundgesetze der Arithmetik (Foundations of Arithmetic), severely criticized this claim, arguing that the universality of mathematics is derived not from the commonality of mental experiences, but from its logical characteristics. Frege further attempted to derive mathematical principles from logic and set theory.

Husserl’s criticism

In his Philosophy of Arithmetic (1891), Husserl tried to derive the principles of arithmetic from psychological phenomena. Frege criticized Husserl’s position and labeled it as psychologism. To answer Frege’s criticism, Husserl re-examined his position and gave up his earlier claims. Husserl departed from psychologism and delivered thorough criticism of it in his Logical Investigations.

Husserl argued that logical principles are universal, a priori truths that cannot be reduced to natural facts, while psychologism entailed skepticism and relativism, which negates the possibility of any such a priori and universal truth. Husserl’s turn from his ealier psychologism was important since it led him to the idea of phenomenology, which became one of the major philosophical movements in the twentieth century.

Husserl argued that science studies knowledge that is considered as a “matter of fact.” The validity of scientific knowledge is limited by its historical time period; in other words, scientific truths are only valid at a certain point in history. Thus, truth in science lacks necessity and strict universality. However, truth in philosophy, as far as Husserl conceived it, must be necessarily true and strictly universal. Husserl argued that truth in philosophy must be, as he called it, an “apodictic truth” whose negation is inconceivable. Psyhologism failed to realize this distinction between science and philosophy and their distinct conception of truth. By attempting to reduce all knowledge into psychological facts, psychologism undermines the foundation of truth while developing relativism and skepticism. With this conviction, Husserl gradually developed the idea of phenomenology.

Contemporary psychologism

Under the influence of Frege, Wittgenstein, and G. E. Moore, analytic philosophy developed without falling into psychologism. However, there has been a recent trend of analytic philosophers who base their position in psychologism due to the collaboration of philosophy with the cognitive sciences, computer sciences, and brain physiology.


  • Cavallin, Jens, and J. Cavallin. Content and Object: Husserl, Twardowski and Psychologism. Springer, 2006. ISBN 9780792347347
  • Frege, Gottlob, and J. L. Austin. The Foundations of Arithmetic: A Logico-Mathematical Enquiry into the Concept of Number. Northwestern University Press, 1980. ISBN 9780810106055
  • Kush, Martin. Psychologism (Philosophical Issues in Science), Routledge, 1995. ISBN 9780415125543
  • Jacquette, Dale. Philosophy, Psychology, and Psychologism: Critical and Historical Readings on the Psychological Turn in Philosophy. Springer, 2003. ISBN 9781402013379
  • Mill, John Stuart. A System of Logic. University Press of the Pacific, Honolulu, 2002. ISBN 1410202526

External links

All links retrieved June 12, 2015.

General Philosophy Sources


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