We might even adopt the method by which he compares the second barbarism with the first, and present the later history of thought as a "reflux" of Vico's ideas. In the first place his criticism of Descartes' immediate knowledge recurs, together with his conversion of the true with the created, in the speculative movement beginning with Kant and Hegel and culminating in the doctrine of the identity of truth and reality, thought and existence. His unity of philosophy and philology recurs in the vindication of history against the scepticism and intellectualism of the eighteenth century due to Cartesianism; in the à priori synthesis of Kant which reconciles the real and the ideal, experience and the categories; and in the historical philosophy of Hegel, the greatest exponent of nineteenth-century historical tendencies. This unity of philosophy and philology, a unity with Vico sometimes confused and impure in method, recurred in its faulty aspects also in the Hegelian school; so that this mental tendency might with justice be entitled "Vicianism." The limitation which Vico tried to impose on the value of mathematics and exact science recurred, as did his criticism of the mathematical and naturalistic conception of philosophy, in Jacobi's critique of Spinozistic determinism and Hegel's of the abstract intellect; and in the case of mathematics in particular Dugald Stewart and others recognised that its validity lay not in the postulates but in the definitions, and the "fictions" of which Vico speaks reappear in the modern terminology of the philosophy of these sciences. His poetical logic or science of the imagination passes into Aesthetic, so ardently studied by the philosophers, literary men and artists of Germany in the eighteenth century, brought by Kant into great prominence by his criticism of the Leibnitian doctrine of intuition as confused conception, and further advanced by Schelling and Hegel, who place art among the pure forms of the mind and so approach the position of Vico. Romanticism too, especially in Germany but also more or less in other countries, was Vician, emphasising as it did the original function of the imagination. His doctrines of language recurred when Herder and Humboldt treated it not intellectualistically as an artificial system of symbols, but as a free and poetic creation of the mind. The theory of religion and mythology abandoned the hypotheses of allegory and deception, and with David Hume recognised that religion is a natural fact, corresponding to the beginnings of human life in its passionate and imaginative state; with Heyne, that mythology is "symbolic speech," a product not of arbitrary invention but of necessity and poverty, of the "lack of words," which finds expression "in comparisons with things already known" (_per rerum iam tum notarum similitudines);_ and with Ottfried Müller, that it is impossible to understand mythology without entering into the very heart