Modern thought, at the end of the Renaissance, begins with an attempt at eliminating that static conception of truth, in which both Platonism and naturalism find the roots of their transcendence. This is the origin of the idea of Progress, first established by Bruno, by Bacon, by Pascal, by Vico, in the form of a correlation between truth and time. Mediæval thought had been shackled for centuries by the authority of the ancients; the new thinkers invoked the authority of antiquity, of old age, and, therefore, of wisdom, not for the distant ages, in which the world could be said to be still young and inexperienced, but for their own times, in which it was possible to add a perpetually new experience and thought to that which had been bequeathed by the thinkers of Greece and Rome. The consequence of this attitude was the discovery of the immanence of truth in life, the liberation from the principle of authority (which had been the characteristic mediæval form of transcendence), and a vigorous impulse towards the recognition of the dynamic nature of reality, of what an American philosopher called the continuity of the ideal with the real. The thought that was contained in germ in those early polemics, vaguely and mythically in Bruno, and much more consciously in Vico, is substantially that of Croce's identification of philosophy with history. We do not expect of a new philosophy that it should suddenly, as a revelation or illumination, give us a key to all the problems of reality, and resolve, once and forever, the so-called mystery of the universe. If such a thing should ever happen, it would mean the end of life, which cannot be conceived, in its ultimate essence, otherwise than as a perpetual positing and solution of problems. It must not be forgotten that a philosophy is the work of one man, and, therefore, contains only the answers to the problems that are real to him. But if we stop to consider the whole course of thought in the last two centuries, we shall realize that the idea of Progress, in many different and even in contrasting forms, is the one around which all our life, theoretical and practical, has centred in modern times. And of that idea, Croce's philosophy is the most powerful and coherent expression that has ever appeared. It is only by considering the whole of reality as activity, and the values of reality as coinciding with the forms of that activity, that Progress acquires a definite meaning: a progress which should be a constant approximation towards a preëxistent ideal, or a material process external to ourselves, would be a purely illusory one. In one case, our whole life would tend towards making a duplicate of that which already is--a work, therefore, without intrinsic worth, and without a real end; in the other, there would be no work at all, no activity, no life.