In 1872 he was elected master of conferences at the Ecole Normale, and was made doctor of philosophy in recognition of his two treatises, Platonis Hippias Minor sive Socratica contra liberum arbitrium argumenta and La Liberte et le determinisme.
It has been held in various forms. In its extreme form it maintains that the individual is absolutely free to chose this or that action indifferently (the liberum arbitrium indifferentiae), but most libertarians admit that acquired tendencies, environment and the like, exercise control in a greater or less degree.
It is the extreme antithesis of Indeterminism or Indifferentism, the doctrine that a man is absolutely free to choose between alternative courses (the liberum arbitrium indiferentiae).
He explains the possibility of error on the ground that the mind possesses the liberum arbitrium indifferentiae and can always refuse to affirm the truth of a conclusion drawn from premises which are not selfevident.