in philosophy, the view that problems of epistemology (i.e., of the validity of human knowledge) can be solved satisfactorily by the psychological study of the development of mental processes. John Locke's Essay Concerning Human Understanding (1690) may be regarded as the classic of psychologism in this sense. A more moderate form of psychologism maintains that psychology should be made the basis of other studies, especially of logic. A classical attack on both forms of psychologism was Edmund Husserl's Logische Untersuchungen (1900-01; "Logical Investigations").
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