In passing from School to School the post-Aristotelian philosophy assumed, as might be expected, various modifications of character in course of time; nevertheless, it retained a certain mental habit and certain common elements. Such was the neglect of intellectual originality, which drove some thinkers to a sceptical denial of all knowledge, and induced others to take their knowledge at second hand from older authorities. Such was the prominence given to practical over speculative questions. Such was the disregard for natural science, and, in comparison with former times, the greater importance attached to theology, apparent not only in the controversy between the Epicureans and Stoics, but also in the apologetic writings of the Stoics and Platonists. Such, too, was the negative morality which aimed at independence of the outer world, at mental composure, and philosophic contentment; the separation of morals from politics; the moral universalism and citizenship of the world; the going within self into the depths of the soul, the will, and the thinking powers; the deepening of the consciousness accompanied at the same time by a narrowing and isolation of it, and the loss of a lively interest in the outer world, and in the simple scientific study thereof. [C. Development of post-Aristotelian philosophy.] [(1) Dogmatic Schools.] [(a) Stoics and Epicureans.] This mental habit, first of all, found simple dogmatic expression in philosophical systems. Not only moral science, but also logic and natural science, were treated in a way consonant with it, although they were partially built upon older views. In dealing with the moral problem, two Schools come to view, markedly different and decided in their peculiarities. The Stoics regard almost exclusively the universal element in man who seeks contentment within, the Epicureans catch at the individual side of his being. The Stoics regard man exclusively as a thinking being, the Epicureans as a creature of feeling. The Stoics make happiness to consist in subordination to the law of the whole, in the suppression of personal feelings and inclinations, in virtue; the Epicureans in individual independence of everything external, in the unruffled serenity of the inner life, in painlessness. The theoretical bases of their teaching correspond with these fundamental ethical positions. [(b) Dogmatic scepticism.]