Anti-psychologism


In logic, anti-psychologism 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 approach to logic originated in the work of Bernard Bolzano.
The concept of logical objectivism or anti-psychologism was further developed by Johannes Rehmke and Gottlob Frege, and has been the centre of an important debate in early phenomenology and analytical philosophy. 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.
The psychologism dispute 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 and anti-psychologism as a kind of externalism.
Psychologism was defended by Theodor Lipps, Gerardus Heymans, Wilhelm Wundt, Wilhelm Jerusalem, Christoph von Sigwart,, and Benno Erdmann.
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. Psychologism was criticized in logic also by Charles Sanders Peirce whose fields included logic, philosophy, and experimental psychology, and generally in philosophy by Maurice Merleau-Ponty who held the chairs of philosophy and child psychology at the University of Paris.
Psychologism is not widely held amongst logicians today, but it does have some high-profile defenders, for example Dov Gabbay.