"To Epicurus we owe the general concurrence of reflecting men in succeeding times in the important truth that men cannot be happy without a virtuous frame of mind and course of life,--a truth of inestimable value, not peculiar to the Epicureans, but placed by their exaggerations in a stronger light; a truth, it must be added, of less importance as a motive to right conduct than to the completeness of moral theory, which, however, it is very far from solely constituting. With that truth the Epicureans blended another position,--that because virtue promotes happiness, every act of virtue must be done in order to promote the happiness of the agent. Although, therefore, he has the merit of having more strongly inculcated the connection of virtue with happiness, yet his doctrine is justly charged with indisposing the mind to those exalted and generous sentiments without which no pure, elevated, bold, or tender virtues can exist." The Stoics were a large and celebrated sect of philosophers; but they added nothing to the domain of thought,--they created no system, they invented no new method, they were led into no new psychological inquiries. Their inquiries were chiefly ethical; and since ethics are a great part of the system of Greek philosophy, the Stoics are well worthy of attention. Some of the greatest men of antiquity are numbered among them,--like Seneca, Epictetus, and Marcus Aurelius. The philosophy they taught was morality, and this was eminently practical and also elevated.