Finally, Vico's providence, the rationality and objectivity of history, which obeys a logic different from that attributed to it by the fancies and illusions of the individual, acquires a more prosaic name, but without changing its nature, in the "cunning of the reason" formulated by Hegel: it appeared again, ingeniously but perversely treated, in Schopenhauer's "cunning of the species," and again, treated with little ingenuity on a purely psychological method, in Wundt's so-called law of the "heterogenesis of ends." Almost all the leading doctrines of nineteenth-century idealism, we have seen, may be regarded as refluxes of Vician doctrines. Almost all; for there is one of which we find in Vico not the premonition but the necessity, not a temporary filling but a gap to be filled. Here the nineteenth century is no longer a reflux of, but an advance upon Vico; and discordant voices of warning or reproach rise up against him. His distinction of the two worlds of mind and nature, to both of which the criterion of his theory of knowledge, the conversion of the truth with the thing created, was applicable, but applicable to the former by man himself because that world is a world created by man, and therefore knowable by him, to the second by God the Creator, so that this world is unknowable by man; this distinction was not accepted by the new philosophy, which, more Vician than Vico, made the demigod Man into a God, lifted human thought to the level of universal mind or the idea, spiritualised or idealised nature, and tried to understand it speculatively in the "Philosophy of Nature" as itself a product of mind. As soon as the last remnant of transcendence was in this way destroyed, the concept of progress overlooked by Vico and grasped and affirmed to some extent by the Cartesians and their eighteenth-century followers in their superficial and rationalistic manner shone out in its full splendour.