Whether the conception of progress is formulated and thrown into relief by Vico is quite another question. Vico does not deny progress; he even refers to it in speaking of the conditions of his own time as an actual fact: but he has no conception of it and still less does he throw such a conception into relief. His philosophy, while it attains the lofty vision of the process of mind in obedience to its own laws, nevertheless retains by reason of this failure to apprehend the progressive enrichment of reality an element of sadness and desolation. The individual character of men and events is obliterated in Vico; individuals and events are represented merely as particular cases of one aspect of the mind or of one phase of civilisation. Hence we always find Aristides alongside of Scipio and Alexander alongside of Caesar: never Aristides simply as Aristides, Scipio as Scipio, and Alexander and Caesar as Alexander and as Caesar. Progress implies that each fact and each individual has its own unique function; each makes its own contribution, for which no other can be substituted, to the poem of history; and each responds with a deeper voice to the one that went before. But the reason why Vico was bound to miss the idea of progress and why his studies in history were inevitably one-sided can be clearly perceived only after a review of his metaphysics. CHAPTER XII METAPHYSICS By "metaphysics" we understand Vico's conception of reality as a whole, not of the world of man by itself; and we also include in the meaning of the word his ultimate negative conclusion asserting the unknowability or the imperfect knowability of one or more spheres of reality, or of that highest sphere in which the others reunite. In point of fact, as we observed in considering the second and latest form of his theory of knowledge, Vico drew a sharp line between the world of man and the world of nature: the former transparent to man because created by him, the latter opaque, because only God its Creator has knowledge of it. And his conception of the total and ultimate reality, the metaphysic which he expounds together with his earlier theory of knowledge, retains the value granted to it by that theory and no other: it is a probable conjecture, but one incapable of verification, and reaches completion in the certitude of revealed theology. Hence this metaphysic remains out of all possible connexion with the New Science, which proceeds by the certain method of truth and cuts itself off from revelation. Vico never rejected it. He discusses it in his autobiography of 1725, the year of the first _Scienza Nuova;_ he refers to it with satisfaction in 1737, seven years after the second _Scienza Nuova,_ when his scientific life was, as he himself considered, at an end. But though he never rejected it he always kept it aside, so to speak, in a corner of his mind.