James Frederick Ferrier (16 June 1808, Edinburgh – 11 June 1864, St Andrews) was a Scottish metaphysical writer. He introduced the term epistemology.
Ferrier’s first contribution to metaphysics was a series of articles in Blackwood’s Magazine (1838–1839), entitled An Introduction to the Philosophy of Consciousness. In these he condemns previous philosophers for ignoring in their psychological investigations the fact of consciousness, which is the distinctive feature of man, and confining their observation to the so-called states of the mind. Consciousness comes into manifestation only when the man has used the word with full knowledge of what it means. This notion he must originate within himself. Consciousness cannot spring from the states which are its object, for it is in antagonism to them. It originates in the will, which in the act of consciousness puts the “I” in the place of our sensations. Morality, conscience, and responsibility are necessary results of consciousness.
Ferrier’s matured philosophical doctrines find expression in the Institutes of Metaphysic the Theory of Knowing and Being (1854), in which he claims to have met the two-fold obligation resting on every system of philosophy, that it should be reasoned and true. His method is that of Spinoza, strict demonstration, or at least, an attempt at it. All the errors of natural thinking and psychology must fall under one or other of three topics: Knowing and the Known, Ignorance, and Being. These are all-comprehensive, and are therefore the departments into which philosophy is divided, for the sole end of philosophy is to correct the inadvertencies of ordinary thinking.