=1. The First Phase of Philosophic Skepticism is called Pyrrhonism= (from about 300 to 230 B. C.). This was a Skepticism _directed against the assumptions of the philosophy of Aristotle_. From the dates above it will be seen to be contemporary with the founding of the Stoic and Epicurean Schools, at the very beginning of the period. The two representatives were Pyrrho (365–275 B. C.) of Elis and his pupil Timon (320–230 B. C.) of Phlius. When Zeno had begun to teach in the Painted Porch and Epicurus in the Gardens, when Theophrastus had succeeded his master in the Lyceum and Polemo led the Academy, the Skeptic Pyrrho began his personal instruction in the city of Elis. Pyrrho had but little influence. He left no writings, and his doctrine became known to the ancients through his pupil, Timon, who was the literary exponent of this Skepticism. The teaching may be stated in the three following sentences: (1) We can know nothing of the nature of things, but only of the states of feeling into which they put us; (2) The only correct attitude of mind is to withhold all judgment and restrain all action; (3) The result of this suspense of judgment is ataraxia or imperturbability. The Skeptic therefore sought the same internal peace for which Stoic and Epicurean were seeking, but he was skeptical of the Aristotelian metaphysics as an instrument to gain it. The opposite of any conclusion being equally plausible, suspense of judgment is the only peace of mind. Pyrrhonism reminded the age after Aristotle that the problem of the certitude of knowledge is fundamental and must be settled before any philosophy can be constructed. The School was short lived, and people disposed to be skeptical joined the Academy. =2. The Second Period of Philosophic Skepticism――The Skepticism of the Academy= (280–129 B. C.). The Middle Academy and its Skepticism was directed particularly against the Stoic teaching that an “apprehensive presentation” guaranteed its own truth by the conviction of immediate certainty. The two most distinguished representatives of this Skeptical period of the Academy were Arcesilaus (315–241 B. C.) and Carneades (214–129 B. C.). Carneades must be mentioned particularly as a genius and a philosopher of great personal influence. “He was the greatest philosopher of Greece in the four centuries from Chrysippus to Plotinus; indeed, in ability and depth of thought he surpassed Chrysippus.”[38] Carneades was the most formidable opponent of the Stoics. He had listened to the Stoic lecturers, had studied their writings, and had refuted them on their own grounds in brilliant lectures of his own.