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 beginningof 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 distinguishedrepresentatives 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.
The Skepticism of the Academy arose somewhat in this way. The rivalry of the Porch and the Older Academy had grown apace and had been a battle between two dogmatic Schools. The Academy was being worsted, its ancient spirit was waning, and it had gradually deserted speculation for ethics. Under Arcesilaus it was provoked to new life by the aggressive dogmatism of the Stoics. Speculation, which it had ignored, it now began to antagonize openly. Arcesilaus, in directing his attack against the doctrine of “apprehensive presentation” of the Stoics, came to conclusions but slightly different from Pyrrho. Carneades laid out for himself a twofold task: (1) to refute all existing dogmas, and (2) to evolve a theory of probability as the basis for practical activity.He applied his Skepticism not only to speculation, like Arcesilaus, but also to ethics and religion.[39]
The Academy did not fully adopt Skepticism, but used it as a weapon against the Stoics. The Platonic tradition was kept alive within the School, and Skepticism made no advance in the Academy after Carneades. It did not even continue in the path marked out by him. In the next generation the Academy became eclectic.
3. The Third Period of Philosophic Skepticism—Sensationalistic Skepticism (during two centuries or more of the Christian era). The chief representatives were Ænesidemus of Cnossus (first century A. D.), Agrippa (about 200 A. D.), and Sextus Empiricus (about 200 A. D.).
This phase of Skepticism was represented mainly by physicians, with arguments based upon empirical physiological grounds. When the Academy passed from Skepticism to eclecticism, Skepticism became centred in Alexandria. For two centuries before Galen (131–201 A. D.) great discoveries had been made in medicine, but the meaning of the discoveries had not been apprehended. There was a general feeling among physicians of that time that there is no such thing as scientific certainty; and skeptical arguments were constructed; based on the empirical discoveries of the scientific circle of Alexandria. While the arguments of the Academy were mostly formal attacks against the Stoics, this Skeptical School of physicians returned to Pyrrhonism, immensely reinforced with scientific material. It strove in vain to disassociate itself from the Academy, for it used in one way or another the formal arguments of the Skeptics of the Academy. In his eight books on Pyrrhonism, Ænesidemus developed the reasons which induced Pyrrho to call in question the possibility ofknowledge. These are known in philosophy as the ten “tropes,” or ten ways of justifying doubt.[40] They were badly arranged by Ænesidemus and reduced to five by Agrippa.[41]
The Last Century and a Half of the Ethical Period. (150 B. C.–1 A. D.). Eclecticism.—About 150 B. C. the Ethical Period became eclectic. After 150 years of passionate controversy the Schools began to compromise their differences and fuse into one another. They no longer emphasized their differences, but began to point to their common ground of unity. This tendency to fusion applies only to the Lyceum, the Academy, and the Porch. The Epicurean School was never a party to this eclecticism and always remained relatively stationary. The fusion occurred only in the teaching of the Schools and not in their organization. Externally the Schools remained separate bodies for six hundred years longer. In the second century Hadrian and the Antonines endowed separate chairs for them in the University of Athens. They were not abolished as Schools until 529 A. D., by Justinian. Internally their independent growth lasted only during the two centuries down to the year 150 B. C. At this time their theoretic mission had been completed. Their internal history from 100 B. C. to 529 A. D. was one of compromise and adjustment. The year 150 B. C. is therefore important. At this time the records of the Schools stop, controversy abates, Stoicism and Epicureanism are introduced into Rome, and fusion of doctrines begins.
The Stoic School was the first to incline to eclecticism. Its own doctrine was a kind of fusion of incoherentparts, and among the Schools it could most easily welcome new doctrines. About 150 B. C., under the lead of Panætius and Posidonius, it adopted many of the Platonic and Aristotelian teachings, tempered its own ethical rigorism, and extended its scientific interests. At the same time the Peripatetics of the Lyceum united the pantheism of the Stoics to their own theism. After the death of Carneades in 129 B. C. the Academy turned from Skepticism back to the Platonic tradition, but it was a meagre Platonism adulterated with many foreign elements. For example, Antiochus of Ascalon taught Cicero from the Academy at Athens in the winter of 79–78 B. C. that Platonism and Aristotelianism were only different aspects of the same doctrine.
There were two factors that prepared an easy way for the rapid spread of eclecticism. One was the growing Skepticism that was so fundamental in Hellenism, and the other was the adoption of Hellenic culture by the Romans. Eclecticism is, after all, only another form of Skepticism. Both exhibit the spirit of undecided conviction. Neither has regard for the bonds of tradition, for both regard the individual superior to every tradition or system. Eclecticism, indeed, attempts to reconcile differing systems; but in doing this it casts a doubt upon the infallibility of them all only to a lesser degree than Skepticism. The spread of eclecticism was therefore only an extension from Greece of the skeptical spirit upon the world, and the Roman world gave a glad welcome to such a spirit. The Roman character was naturally eclectic. After his first aversion the Roman was hospitable to all philosophies and religions. In his practical way, undisturbed by philosophical hair-splittings, he selected from the different systems whatwas suited to his practical needs. Eclecticism found fertile ground in Roman civilization.