=The Practical Presupposition of the Enlightenment――The Independence of the Individual.= The “new man” emerged from the Renaissance as the most important object of consideration, and during the Enlightenment there was never the slightest question about his independence. The individual became the original datum of this period into which we are now entering; he was considered to be the only thing that is self-intelligible; he was the starting-point from which all social relationships were to be explained. Among the many problems that arose, the independent existence of the individual remained unquestioned. It was the period of “liberty, equality, and fraternity.” The problems were about the relations of the individual; never about the individual himself, for concerning the individual no problem could arise. The individual rejoicing in the exuberance of his own powers, the “monad enjoying himself,” dominated everything. The monadology of the Renaissance became an atomism in the Enlightenment. The individual was the practical assumption of the period. =The Metaphysical Presupposition of the Enlightenment.= There was a metaphysical background to this practical assumption of the individual. This was the Cartesian dualism of mind and matter. Although the eighteenth century despaired of a successful metaphysical construction of the “new universe,” and although its attention was riveted on an analysis of human relationships, it must not be supposed that the period was without its metaphysical bias. Such is not the nature of human history; and if an epoch refuses to discuss metaphysical questions, it is because it assumes some metaphysics as true. The assumption of the independent individual implies the independent existence of matter. The Enlightenment assumed the Cartesian theory as correct. While many were the polemics against metaphysical speculation, the Cartesian dualism was nevertheless in control. Here within is the independent existence of mind; and it would naturally follow that there without is the equally independent existence of matter. The conception might fade into a ghost-like dualism, as in Berkeley and Hume, but the dualism never entirely vanished. This has since been known as the philosophy of “common sense,” and is to-day the easy attitude of those not interested in metaphysical discussions. “Common sense” means the opinion of the majority as to truth. Most people to-day, as then, accept without question some sort of dualism, usually the dualism of mind and body.