=The Problems of the Enlightenment.= The area of inquiry was thus very much restricted during this period. Nature lies beyond our ken. God is still more incomprehensible. From the study of nature and God, let us turn to a study of the problems of the inner life. Yet while the field of study was restricted, the problems within it were multitudinous, and there was an astonishing breadth and universality, a tenacity of everything, a disdainfulness of nothing. Within its own field the Enlightenment sought to systematize and to stand by any idea in spite of all opposition. The imagination took bold flights and, from the standpoint of the inner individual life, tried to transform its world. Overloaded with ballast, it tried to reconcile the irreconcilable and to overlook the brute facts of existence. The problems arise from an age that is self-opinionated, self-tormenting, and subjective. The problems of this age may be divided into two classes,――utilitarian and critical,――both having reference to the individual man in his relations. These include the problems of psychology, epistemology, sociology, economics, politics, etc. There was, for example, the problem of our knowledge of the external world, of the validity of innate ideas as the basis of knowledge, of the rational basis of religion. Thought was very alert at this time, as is always the case in times of great individualism, and thought could move with great rapidity over the wide range of such subjects. (a) =Utilitarian Problems.= The Enlightenment was curious about the interests, the happiness, and the many powers of the individual. Empirical psychologists and brilliant ethical scholars appeared. How much can man know, and what are the limits and extent of his knowledge? The Rationalists of the Renaissance had accepted without question the mediæval teaching that a group of our ideas is innate and therefore God-given. The Middle Ages had been built up on revealed knowledge. But to the thinkers of the Enlightenment the most important ideas――yea, the only ideas of service to us――are those derived from experience. We should be happier if we confined ourselves to the facts of every-day life, and did not try to deal with things beyond experience. Let us give metaphysical theories to the Churchman. Empirical psychology thus took the place of metaphysics, and became known as philosophy. It was the favorite science of the time, and the basis of ethics and epistemology. Philosophy thus came out of the school, and became a public utility. It was based, to be sure, upon theological preconceptions, but it was to be put to the service of man. It was to be an instrument of discovery as well as a means of grace. With this psychological incentive great schools of moralists arose, especially in England: studying morality as based on the intellect, on the feelings, on authority, on the association of ideas.