As history is reduced to philosophy through the identification of the historical with the individual judgment, so philosophy is reduced to history through the identification of the definition with the individual judgment. Since every philosophical proposition is an answer to a given question, and every question or problem is individually and historically determined, the whole course of the history of philosophy is in constant function of the general course of history. This is the truth contained in Hegel's formula of the identity of philosophy and history of philosophy, which had been revived in Italy, when Croce was meditating on these problems, by his friend Gentile: a formula which he finally accepted and transformed into that of the identity of history and philosophy, in accordance with his view of philosophy as a moment or grade of the spirit of man. The _a priori_ synthesis which constitutes the reality both of the definition and of the individual judgment is, at the same time, the reality of both philosophy and history. The distinction between the two is a purely didactic one: in the first the emphasis is laid on the definition and the system, in the second on the individual judgment and the narrative. But because the narrative includes the concept, every narrative clarifies and solves philosophical problems, and, on the other hand, every system of concepts throws light on the facts which are present to the mind. The confirmation of the soundness of the system is in the power it displays to interpret and narrate history; the touchstone of philosophy is history. The concept, in affirming itself, conquers the whole of reality, which becomes one with it. We shall deal more briefly with Croce's treatment of the organization of the empirical and abstract concepts in the natural and mathematical sciences because his views coincide in their general lines with the economic theory of science, which is the view of scientific method elaborated by the scientists themselves in the last decades, and differ from it only in so far as they are comprehended in a vaster system of thought. Croce's polemic against pseudo-scientific philosophy, which was amply justified at the beginning of his career, has now lost a good deal of its actuality, since the ambitious attempts to organize the concepts of science into a system of ultimate truth have finally collapsed under the blows inflicted on their authors by science itself, and are now relegated into a few academic and journalistic backwaters. On the other hand, there is no doubt that his discussion of scientific methods, though sufficient for his purposes, is far from being as exhaustive as his discussion of either art or philosophy.