Renouvier was the first French philosopher after
Nicolas Malebranche to formulate a complete
idealistic system, and had a vast influence on the development of French thought. His system is based on
Immanuel Kant's, as his chosen term
neocriticism (
néo-criticisme) indicates; but it is a transformation rather than a continuation of Kantianism. The two leading ideas are the dislike of the "unknowable" in all its forms, and a reliance on the validity of personal experience. The former accounts for Renouvier's acceptance of Kant's
phenomenalism, combined with rejection of the
thing-in-itself. It accounts, too, for his polemic on the one hand against a Substantial Soul, a
Buddhistic Absolute, an Infinite Spiritual Substance; on the other hand against the no less mysterious material or dynamic substratum by which naturalistic
Monism explains the world. He maintains that nothing exists except presentations, which are not merely sensational, and have an objective aspect no less than a subjective. To explain the formal organization of our experience, Renouvier adopts a modified version of the Kantian categories. The insistence on the validity of personal experience leads Renouvier to a yet more important divergence from Kant in his treatment of
volition.
Liberty, he says, in a much wider sense than Kant, is man's fundamental characteristic. Human freedom acts in the
phenomenal, not in an imaginary
noumenal sphere.
Belief is not merely
intellectual, but is determined by an act of
will affirming what we hold to be morally good. Renouvier's dislike of the
unknowable also led him to take up arms against the notion of an
actual infinite. He believed that an infinite sum must be a name for something incomplete. If one begins to count, "one, two, three ..." there never comes a time when one is entitled to shout "
infinity"! Infinity is a project, never a fact, in the neocritical view. Renouvier became an important influence upon the thought of American
psychologist and philosopher
William James. James wrote that "but for the decisive impression made on me in the 1870s by his masterly advocacy of
pluralism, I might never have got free from the monistic superstition under which I had grown up." ==Religious views==