It will easily be seen that this explanation of the deductive process completely turns the tables on the transcendental school. All reasoning is shown to be at bottom inductive. Inductions and their interpretation make up the whole of logic; and to induction accordingly Mr. Mill devoted his chief attention. For the first time induction was treated as the _opus magnum_ of logic, and the fundamental principles of science traced to their inductive origin. It was this, taken with his theory of the syllogism, which worked the great change. Both his "System of Logic" and his "Examination of Sir William Hamilton's Philosophy" are for the most part devoted to fortifying this position, and demolishing beliefs inconsistent with it. As a systematic psychologist Mr. Mill has not done so much as either Professor Bain or Mr. Herbert Spencer. The perfection of his method, its application, and the uprooting of prejudices which stood in its way,--this was the task to which Mr. Mill applied himself with an ability and success rarely matched and never surpassed. The biggest lion in the path was the doctrine of so-called "necessary truth." This doctrine was especially obnoxious to him, as it set up a purely subjective standard of truth, and a standard--as he was easily able to show--varying according to the psychological history of the individual. Such thinkers as Dr. Whewell and Mr. Herbert Spencer had to be met in intellectual combat. Dr. Whewell held, not that the inconceivability of the contradictory of a proposition is a proof of its truth co-equal with experience, but that its value transcends experience. Experience may tell us what _is_; but it is by the impossibility of conceiving it otherwise that we know it _must be_. Mr. Herbert Spencer, too, holds that propositions whose negation is inconceivable have "a higher warrant than any other whatever." It is through this door that ontological belief was supposed to enter. "Things in themselves" were to be believed in because we could not help it. Modern Noumenalists agree that we can know nothing more of "things in themselves" than their existence, but this they continue to assert with a vehemence only equalled by its want of meaning.