The German philosopher Jakob Friedrich Fries (1773-1843), interested in the phenomenon of the mind, advanced psychological philosophy in the direction of psychological empiricism.

Jakob Friedrich Fries, born in Barby, Saxony, on Aug. 23, 1773, studied at Leipzig and Jena. He became dozent at Jena in 1801, professor of philosophy and elementary mathematics at Heidelberg in 1805, and professor of philosophy in 1814. In 1816 Fries accepted the chair of theoretical philosophy at Jena.

Fries was one of the links in a chain which gradually transformed psychology from metaphysics to empiricism, from philosophy to science. A disciple of Immanuel Kant, he did not agree with Kant on all points but sought rather to reshape and elaborate the principles of critical philosophy. He was thus considered by some an opponent of Kant. Perhaps "semi-Kantian" describes him best, for the system which Fries developed was really midway between that of Kant and that of the "commonsense" school...