A survey of the final product of western thought, theoretical and practical, over the last fifteen hundred years, is not exactly encouraging. The final conclusion of western wisdom—that all transcendence has got to go, once and for all—is not really applicable in the field of knowledge (for which it is actually intended), because we cannot do without metaphysical guidance here: when we think we can, all that is apt to happen is that we replace the grand old metaphysical errors with infinitely more naïve and petty ones. On the other hand, in the field of life the intellectual middle class has set in motion a practical metaphysical liberation which the noble apostles of that freedom—I mean principally Kant and the philosophers of the Enlightenment—would have shuddered to behold. Our condition, as has often been observed, bears a frightening resemblance to the final stage of the ancient world. And this resemblance does not consist merely in a lack of religion and morals, but precisely in this point: that both ages think of themselves as set upon a firm, safe course in the field of pragmatic knowledge, on lines which seem, to the conviction of the age, to be, at least in their general form and basic principles, immune from changes of opinion. Then it was Aristotelian philosophy, now it is modern science.