Psychologism

Psychologism is a generic type of position in philosophy according to which psychology plays a central role in grounding or explaining some other, non-psychological type of fact or law. The most common types of psychologism are logical psychologism and mathematical psychologism.

Logical psychologism is a position in logic (or the philosophy of logic) according to which logical laws are grounded in, derived from or explained by psychological facts (or laws). Psychologism in the philosophy of mathematics is the position that mathematical concepts and/or truths are grounded in, derived from or explained by psychological facts (or laws).

John Stuart Mill seems to have been an advocate of a type of logical psychologism, as were many Nineteenth-Century German logicians such as Sigwart and Erdmann. Psychologism was famously criticized by Frege in his review of Husserl's Philosophy of Arithmetic. In the Prolegomenon to his "Logical Investigations" Husserl himself criticized psychologism and sought to distance himself from it.