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.
In his chief work, Neue oder psychologische Kritik der Vernunft (1807; New Critique of Reason), Fries tried to combine the teaching of Kant with elements from Friedrich Heinrich Jacobi's philosophy of faith, basing critical philosophy on psychology and substituting self-observation for the transcendental method. Fries maintained that only that which is sense-perceived can be known and that the principles of reason are immediately known in consciousness. Kant had sought to prove the principles of reason a priori. Fries, however, contended that human beings cannot know the supersensible, or things-in-themselves. They are objects of faith which satisfy the demands of the heart.
Like Kant, Fries discussed psychological facts under the heading of anthropology, considering them in the light of the customs of primitive peoples, and empirically thinking of the mental processes themselves as being the data that psychology had best study. The modern reader can possibly make more relevant sense of Fries by substituting "phenomenological" for Fries's "anthropological."
In 1821 Fries published the Handbook of Psychical Anthropology, in which he divided anthropology into mental and physical aspects. Under mental anthropology he studied the actual processes by which one perceives, remembers, and thinks. The mental processes, although depending upon a pure ego or self, are never known except through their effects. Similarly, the ego or self cannot be appreciated for itself but is known only through its effects. Under physical anthropology Fries discussed the relationship between brain and mind. He distinguished three main faculties: knowledge, inner disposition (Gemüth) or feeling, and activity or will. He regarded each of these faculties as incorporated in or subordinated to the unitary self.
Further Reading on Jakob Friedrich Fries
Virtually all of the important sources on Fries are in German. One of the few works in translation is Rudolf Otto, The Philosophy of Religion Based on Kant and Fries (1921; trans. 1931). For background material see George Sidney Brett, Brett's History of Psychology, edited and abridged by R. S. Peters (1953).