The Graeco-Roman Period (6th century s.c. to 5th century a.n.)— The controversy origi nated in a discussion as to whether morality ex ists by convention (v6p6), by arbitrary enact ment (Ohm), or in reality, that is (in the ter minology of the time),. "by nature" (0.6e4) or in the nature of things. Some of the Sophists taught that morality was a creature of the efforts of the rulers of a community, being a device on their part to keep others in subjection for the better indulgence of their own desires much as many of the "free-thinkers° of the 18th century (in many respects the modern con geners of the Sophists) taught that religion was an invention of state-craft and priest-craft. Others taught that it was a product of social agreement or institution. Some of the nobler Sophists (like Protagoras. see the Platonic dialogue of the same name) interpreted this as praise of the state of civilization and culture as against the raw, crude state of nature, while others taught that it was merely a conventional means to personal satisfaction, and hence had no binding force when short-cuts to happiness were available. In the meantime the actual moral discipline of the Greek city-state was much relaxed, partly because of the intermi nable dissensions of party strife, and partly be cause the religious beliefs which were the foun dation of civic life were fast becoming incredi ble. Socrates (about 470 n.c.-399 "Lc.) was ap parently the first to undertake a positive and constructive analysis of moral ideas. He made the following contributions: (1) All things have to be considered with reference to their end, which indeed constitutes their real °nature)); the end of each thing is its good. Man must therefore have his own end, or good; this is real and inherent, not conventional nor the product of law. (2) To know is to grasp the essential, real being of a thing— its "nature,)) or end; "know thyself is the essence of morality; it means that man must base his activity upon comprehension of the true end of his own being. All evil is really involuntary, based on ignorance or misconception of man's true good. To be, ignorant of the good is the one disgrace. If a man does not know Socrates professed that he did not —he can at least devote himself seriously to inquiring, to the effort to learn. If not wise (a sophist) he can at least be a lover of wisdom (a philoso pher). And until he attains knowledge, the in dividual will be loyal to the responsibilities of his own civic life.
The two conceptions of the good as some how the fulfilment of man's nature or reality, and as attainable only under conditions of rational insight are the bases of all later Greek thought. ()pinions differed to what man's end is, and as to the character of .true knowl edge of it. The extreme division was between the Cynic school, the forerunner of the Stoics, founded by Antisthenes (about 444 ac.-369 s.c.), and the Cyrenaic (the precursor of Epi cureanism, founded by Aristippus (about 435 s.c.-360 s.c.). The former taught that virtue, manifested in temperance or self-control, is the one and only good, pleasure as an end being evil, and that it is known by pure reason. The latter taught that pleasure, known only in feel ing (the sensation of a gentle and continuous change) is the good. The wise man of Socrates is he who knows this moderate and enduring pleasure and is not captured by sudden and vio lent passion. Both schools take a somewhat antagonistic attitude toward the state; the Cynic emphasizing the superiority of the sage to gov ernment and authority, well illustrated in the anecdotes of Diogenes and Alexander the Great; the Cyrenaic holding that the pleasures of friendship and social companionship of the congenial are superior to those of partici pation in public life. These schools thus set two of the fundamental problems of subsequent ethical theory, namely, the nature of the good, and the nature of knowledge of it; and supplied the framework of later schools of thought.
Those who hold that pleasure is the good are termed Hedonists (Gr. 004, pleasure); those who held to its residence in the virtuous will Perfectionists, or (with certain qualifications added) Rigorists. Those who hold that it is known through reason are Intuitionalists, the other school, Sensationalists or Empincists.
Plato (q.v.) (about 427 n.c.-347 B.c.) at tempted a synthesis of the conceptions of the two schools just referred to, with a constructive program of social, political and educational reform, and with a reinterpretation of earlier philosophic theories of the universe and of knowledge. His most characteristic doctrines are (1) the the of the Socratic con ception of the good as constituting the true essence or nature of man. Under the influence of philosophic concepts derived from a variety of sources, Plato conceived man as essentially a microcosm; as the universe in miniature. He is composed of a certain arrangement of the elements of reality itself ; hence he can be truly known only as the real nature of the universal reality which constitutes him is known; his good is ultimately one with the final cause or good of the universe. Thus Plato goes even farther than Socrates in asserting that morality is by nature — it is by the nature not only of man but of absolute reality itself, which is thus given an ethical or spiritual interpretation. Thus he grounded ethics on general philosophic concep tions and has been the model for all since who have distinctly conceived ethics to be a branch of philosophy. Moreover, since he regards the ultimate good of the universe as one with God and as the animating purpose in the creation of physical nature, he brings ethics into connection with religion, and with man's relations to the world about him. (2) Plato regarded the state in its true or ideal form as the best embodiment or expression of the essential nature of indi vidual man; as indeed more truly man than any one individual. In its true organization, it reflects or itnages the constitution of the ultimate good. Thus Plato brings ethics back into con nection with politics as the theory of ideal social organization. Practically, he delineates this state in outline (esliecially in his Republic, and, with greater attention to feasible detail in his Laws), and proposes in view of this ideal a specific reform of the existing order, instead of disregard of it as with Cynic and 'Cyrenaic. (3) He sets forth a scheme of the good as realizable in human nature, which endeavors to combine the one-sided extremes of mere pleas ure and mere virtue. He conceives the good to be the fulfilment of all capacities, facul ties or functions of human nature, the fulfil ment of each power being accompanied with its own appropriate pleasure, and all being ordered and bound together in a harmonious whole by a law of measure or proportion which assigns to each its proper place; at the head, the pleas ure of pure knowledge; at the bottom, the appetites ; between, the pleasures of the nobler senses (sight and hearing), and of the higher impulses—ambition, honor, etc. The right func tioning of each is virtue; its product is pleasure. The system of pleasures according to virtue is the good. Moreover, he specifies four cardinal virtues which result—wisdom, the Icnowledge of the good or organized whole; justice, the law of proportion or measure i courage, the asser tion of the higher tendencies against the pleas ures and pains arising from the contemplation or imagination of the lower; temperance, the law of subordination in accordance with which each lower function is restrained from usurping the place of the higher. Plato's system of ethics remains the standard of ethical theories of the ((self-realization') type.