The harmony which the doctrine of Anaxagoras introduced into the philosophy of Athens, soon attracted attention and multiplied disciples. He was teaching when Socrates arrived in Athens, and the latter attended his school. The influence which the doctrine of Anaxagoras exerted upon the mind of Socrates (leading him to recognize Intelligence as the cause of order and special adaptation in the universe), [465] and also upon the course of philosophy in the Socratic schools, is the most enduring memorial of his name. [466]
[Footnote 465: ][ (return) ] "Phaedo," § 105.
[Footnote 466: ][ (return) ] Aristotle's "Metaphysics," bk. i. ch. iii.
We have devoted a much larger space than we originally designed to the ante-Socratic schools--quite out of proportion, indeed, with that we shall be able to appropriate to their successors. But inasmuch as all the great primary problems of thought, which are subsequently discussed by Plato and Aristotle, were started, and received, at least, typical answers in those schools, we can not hope to understand Plato, or Aristotle, or even Epicurus, or Zeno of Cittium, unless we have first mastered the doctrines of Heraclitus, Pythagoras, Parmenides, and Anaxagoras. [467] The attention we have bestowed on these early thinkers will, therefore, have been a valuable preparatory discipline for the study of
[Footnote 467: ][ (return) ] Maurice's "Ancient Philosophy," p. 114; Butler's "Lectures on Ancient Philosophy," vol. ii. pp. 87, 88.
II. THE SOCRATIC SCHOOL.
The first cycle of philosophy was now complete. That form of Grecian speculative thought which, during the first period of its development, was a philosophy of nature, had reached its maturity; it had sought "the first principles of all things" in the study of external nature, and had signally failed. In this pursuit of first principles as the basis of a true and certain knowledge of the system of the universe, the two leading schools had been carried to opposite poles of thought. One had asserted that experience alone, the other, that reason alone was the sole criterion of truth. As the last consequence of this imperfect method, Leucippus had denied the existence of "the one," and Zeno had denied the existence of "the many." The Ionian school, in Democritus, had landed in Materialism; the Italian, in Parmenides, had ended in Pantheism; and, as the necessary result of this partial and defective method of inquiry, which ended in doubt and contradiction, a spirit of general skepticism was generated in the Athenian mind. If doubt be cast upon the veracity of the primary cognitive faculties of the mind, the flood-gates of universal skepticism are opened. If the senses are pronounced to be mendacious and illusory in their reports regarding external phenomena, and if the intuitions of the reason, in regard to the ground and cause of phenomena, are delusive, then we have no ground of certitude. If one faculty is unveracious and unreliable, how can we determine that the other is not equally so? There is, then, no such thing as universal and necessary truth. Truth is variable and uncertain, as the variable opinion of each individual.
The Sophists, who belonged to no particular school, laid hold on the elements of skepticism contained in both the pre-Socratic schools of philosophy, and they declared that "the σοφία" was not only unattainable, but that no relative degree of it was possible for the human faculties. [468] Protagoras of Abdera accepted the doctrine of Heraclitus, that thought is identical with sensation, and limited by it; he therefore declared that there is no criterion of truth, and Man is the measure of all things. [469] Sextus Empiricus gives the psychological opinions of Protagoras with remarkable explicitness. "Matter is in a perpetual flux, whilst it undergoes augmentations and losses; the senses also are modified according to the age and disposition of the body. He said, also, that the reason of all phenomena resides in matter as substrata, so that matter, in itself, might be whatever it appeared to each. But men have different perceptions at different periods, according to the changes in the things perceived.... Man is, therefore, the criterion of that which exists; all that is perceived by him exists; that which is perceived by no man does not exist." [470] These conclusions were rigidly and fearlessly applied to ethics and political science. If there is no Eternal Truth, there can be no Immutable Right. The distinction of right and wrong is solely a matter of human opinion and conventional usage. [471] "That which appears just and honorable to each city, is so for that city, so long as the opinion prevails." [472]
[Footnote 468: ][ (return) ] Encyclopædia Britannica, article "Sophist."
[Footnote 469: ][ (return) ] Plato's "Theætetus" (άνθρωπος--"the individual is the measure of all things"), vol. i. p. 381 (Bohn's edition).