In imagination we dramatise the Renaissance as a sweeping revolution. Whether humanists or modernists, we look upon it as a beginning, or a resumption, at all events as the turning-point from which we are the continuators in a straight line. Historians of philosophy, of letters, of politics, of science all concur. More impressively still the men of the Renaissance themselves were quite conscious of the change--Bessarion, Aldus, Erasmus, da Vinci, Galileo, Bruno, to take names at random. The shift of curiosity from the divine to the secular, and the responsive shift of discipline from scholasticism to humanism opened out new vistas to the voyaging mind. It would be hard to exaggerate the almost theatric reversals which the times witnessed and welcomed. Sweeping as it was, however, the revolution of the Renaissance was less radical than that of the second half of the nineteenth century. In contrast to the latter the changes wrought by the Renaissance were on the level of explicit ideas. The essential stuff of thought was unchanged. New ideas were astir, but the elements of which they were built were the old elements. Theology gave way to humanism; God as the centre gave way to man as the centre. But after all, God had been conceived as a father and man as a child of God, and, God or man, their psychology was the same. The very literature which had laid the premisses of mediæval thought--the Bible--permeated the consciousness of the humanistic period yet more deeply. The shift of discipline from sacred to profane letters, as a consequence, made no profound break in the consciousness itself. The major impulses of the two periods blended easily and naturally. The religious impulse of the Middle Ages lent itself triumphantly to literary expression; there was the _Divine Comedy_. The literary impulse of the Renaissance lent itself no less triumphantly to religious themes; there was _Paradise Lost_. Natural science, indeed, began its modern course under the impulse of the Renaissance. Still, from the fifteenth to the nineteenth century, while the common discipline of the West was humanistic, natural science did not profoundly alter the minds of men. It was an incident, a special play of curiosity and thought on the part of men whose minds were formed and informed in the medium of humane letters. Even Doctor Johnson had his chemical apparatus.