psychologism

Psychologism is the view that logical laws, and sometimes mathematical truths, are grounded in human psychology or the mechanisms of mental processes rather than in timeless, abstract facts about thought. In its strongest form, it holds that the validity of inferences and the truth of logical principles derive from the way people actually think.

Historically, psychologism emerged in the 19th century as some philosophers and logicians sought to connect logic to psychology or to describe logical laws as empirical generalizations about mental operations. The most influential critique came from Gottlob Frege, who argued that logic must be objective and non-empirical; treating logical laws as psychological would render them contingent and threaten the objectivity of mathematics and truth. In the early 20th century, Edmund Husserl developed a thorough counterargument in his Logical Investigations, insisting that logic is a formal science grounded in meanings and intentional acts, not a study of empirical psychological states. The exchange helped steer analytic philosophy toward formal, normative accounts of logic and influenced subsequent movements such as formalism and logicism.

In contemporary discussions, the term psychologism is often used to describe attempts to derive logical or mathematical truths from cognitive processes. While cognitive science and experimental philosophy investigate how people actually reason, this does not equate to redefining logic as a branch of psychology. The prevailing view in analytic philosophy remains that logical validity is a normative relation, not reducible to empirical psychology.