Frege's rationalist epistemology

This thesis examines the rationalist epistemology of the German logicist mathematician Gottlob Frege (1868-1925), whose principal contribution to mathematical logic was the invention of the logical quantifier and application of mathematical functions to propositional functions of logic. Frege is revered for his seminal investigations into semantics. His work is credited by some as having inaugurated the 'linguistic turn.' It has been held that Frege's interests were primarily semantic and not epistemological. The extreme realistic views attributed to him make it seem that he was interested in ontology and an ally of Russell and Moore in the revolt against idealism. He rejected formalism, empiricism and psychologism in logic and mathematics. I argue controversially that Frege was indeed a psychologistic and rationalist philosopher with strong ties to Neo-Kantianism and was concerned with the epistemology of mathematical truth.