This will explain why the short period of modern thought is traditionally divided into comparatively many periods. These subordinate periods ring out the changes through which the modern man feels that he himself has blindly passed in his inner life. Modern philosophy is no more local and temporary than the ancient; it is no less a part of a social movement; but the modern man is more alive to the differentiations of modern thought than he is to those of antiquity. =The Periods of Modern Philosophy.= The divisions of the history of modern philosophy are as follows:―― 1. The Renaissance (1453–1690)――from the end of the Middle Ages to the publication of Locke’s _Essay on the Human Understanding_. 2. The Enlightenment (1690–1781)――to the publication of Kant’s _Critique of Pure Reason_. 3. German Philosophy (1781–1831)――to the death of Hegel. 4. The Nineteenth Century Philosophy (1820–the present time). The Renaissance, the first period, covers more than half of the length of modern times. It is sometimes called the springtime of modern history, although it is longer than all the other seasons together. It is to be noted that two epoch-making books form the dividing lines between the first three periods. The transition from the Renaissance to the Enlightenment is signalized by Locke’s great _Essay on the Human Understanding_, which expressed for one hundred years the political and philosophical opinions of western Europe. The transition from the Enlightenment to German Philosophy was in its turn signalized by the appearance of Kant’s _Critique of Pure Reason_, and this book may be said to have been fundamental to human thinking ever since. There is one point further to be noticed in these divisions, and that is the overlapping of the last two periods. German philosophy ends practically with the death of Hegel in 1831, and the modern Evolution movement began at least ten years before, about 1820. No great philosophical treatise marks the division here, for the Evolution movement had its beginnings in German philosophy and in the discoveries and practical inventions of natural science. Evolution, however, became a reaction upon the last phases of German philosophy, and then formed a distinct movement. The book that formulated the Evolution movement most fully appeared several years after the theory was under way. This was Darwin’s _Origin of Species_, published in 1859. Locke’s _Essay_ and Kant’s _Critique_ are therefore the most influential philosophical interpretations of the history of modern times since its early beginnings in the Renaissance.