Where the subject is matter the distinction between an art and a science is in general easily perceptible. No one confounds the science of projectiles with the art of gunnery, or the art of surgery with the science of anatomy. But it appears to be much less easy to distinguish the arts and the sciences which have for their subject the operations of the human mind. Thus we often talk of the art of logic, and of the science of morality. But logic is not an art but a science. It is not a collection of precepts how to reason, but a statement of the principles on which all reasoning depends. The logician does not advise, he merely instructs. He does not teach us to argue by means of syllogisms, but asserts the fact that all reasoning is syllogistic. His statements are all general; they have no relation to time or to place. They are unconnected with any science but his own. On the other hand, morality is not a science but an art. The object of the moralist is not to inform us as to the nature of the faculties and the sensations of man, but to advise us how to use those faculties, and how to subject ourselves to those sensations, for the purpose of promoting our happiness. He must therefore draw his materials from many different sciences, and must vary his precepts according to the social condition of those whom he addresses. The morality of the Stoics was fitted to an aggregate of petty communities constantly engaged in foreign and civil war, in which defeat involved the worst of human evils, the loss of life, of relations, of property, and of liberty. No Greek could be sure that in a year’s time his country might not be conquered by a neighbouring tribe, or his party overthrown by a revolution, and all his family and friends murdered before his eyes, or sold with him into slavery. Under such circumstances, insensibility, the power of enduring the approach and the presence of evil, and the insecurity, and even the absence of good, appeared to be the quality most conducive to happiness. The Stoic moralist, therefore, was as anxious to blunt the desires and harden the perceptions of his pupils, as the English moralist is to rouse their ambition, and to expand their sensibility. The logic of Aristotle and the logic of Whately are the same, but how little do we find in common when we compare the morality of Zeno with that of Smith or of Paley.