The Approach to Philosophy

by Ralph Barton Perry

But enough has been said to demonstrate the interdependence of ontology and cosmology, of the theory of being and the theory of differentiation and process. Such problems can be only abstractly sundered, and the distinctive character of any metaphysical system will usually consist in some theory determining their relation. Philosophy returns to these metaphysical problems with its thought enriched and its method complicated, after becoming thoroughly alive to the problems of epistemology, logic, and ethics.

Epistemology Seeks to Understand the Possibility of Knowledge.

§ [66]. Epistemology is the theory of the possibility of knowledge, and issues from criticism and scepticism. If we revert again to the history of Greek philosophy, we find a first period of enterprising speculation giving place to a second period of hesitancy and doubt. This phase of thought occurs simultaneously with the brilliantly humanistic age of Pericles, and it is undoubtedly true that energy is withdrawn from speculation largely for the sake of expending it in the more lively and engaging pursuits of politics and art. But there are patent reasons within the sphere of philosophy itself for entailment of activity and taking of stock. For three centuries men have taken their philosophical powers for granted, and used them without questioning them. Repeated attacks upon the problem of reality have resulted in no consensus of opinion, but only in a disagreement among the wise men themselves. A great variety of mere theories has been substituted for the old unanimity of religious tradition and practical life. It is natural under these circumstances to infer that in philosophy man has overreached himself. He would more profitably busy himself with affairs that belong to his own sphere, and find a basis for life in his immediate relations with his fellows. The sophists, learned in tradition, and skilled in disputation, but for the most part entirely lacking in originality, are the new prophets. As teachers of rhetoric and morals, they represent the practical and secular spirit of their age; while in their avoidance of speculation, and their critical justification of that course, they express its sceptical philosophy.

Scepticism, Dogmatism, and Agnosticism.

§ [67]. In their self-justification certain of the sophists attached themselves to a definite doctrine maintained by those of their predecessors and contemporaries who were atomists, or followers of that same Leucippus whom we have quoted. This doctrine was the result of an attempt to construe perception in terms of the motion of atoms. Outer objects were said to give off fine particles which, through the mediation of the sense organs, impinged upon the soul-atom. But it was evident even to the early exponents of this theory that according to such an account, each perceiver is relegated to a world peculiar to his own stand-point. His perception informs him concerning his own states as affected by things, rather than concerning the things themselves. Upon this ground the great sophist Protagoras is said to have based his dictum: Πάντων χρημάτων μέτρον ἄνθρωπος,—"Man is the measure of all things." This is the classic statement of the doctrine of relativity. But we have now entered into the province of epistemology, and various alternatives confront us. Reduce thought to perception, define perception as relative to each individual, and you arrive at scepticism, or the denial of the possibility of valid knowledge. Plato expounds this consequence in the well-known discussion of Protagoras that occurs in the "Theætetus."

"I am charmed with his doctrine, that what appears is to each one, but I wonder that he did not begin his book on Truth with a declaration that a pig or a dog-faced baboon, or some other yet stranger monster which has sensation, is the measure of all things; then he might have shown a magnificent contempt for our opinion of him by informing us at the outset that while we were reverencing him like a God for his wisdom, he was no better than a tadpole, not to speak of his fellow-men—would not this have produced an overpowering effect? For if truth is only sensation, and no man can discern another's feelings better than he, or has any superior right to determine whether his opinion is true or false, but each, as we have several times repeated, is to himself the sole judge, and everything that he judges is true and right, why, my friend, should Protagoras be preferred to the place of wisdom and instruction, and deserve to be well paid, and we poor ignoramuses have to go to him, if each one is the measure of his own wisdom? . . . The attempt to supervise or refute the notions or opinions of others would be a tedious and enormous piece of folly, if to each man his own are right; and this must be the case if Protagoras's Truth is the real truth, and the philosopher is not merely amusing himself by giving oracles out of the shrine of his book."[167:13]

This is the full swing of the pendulum from dogmatism, or the uncritical conviction of truth. A modified form of scepticism has been developed in these later days under the influence of natural science, and is called agnosticism or positivism. It accepts the Protagorean doctrine only in the sense of attributing to human knowledge as a whole an incapacity for exceeding the range of perception. Beyond this realm of natural science, where theories can be sensibly verified, lies the unknowable realm, more real, but forever inaccessible.

The Source and Criterion of Knowledge According to Empiricism and Rationalism. Mysticism.

§ [68]. It is important to note that both scepticism and agnosticism agree in regarding perception as the essential factor in knowledge. So far at any rate as our knowledge is concerned, the certification of being consists in perceivability. Knowledge is coextensive with actual and possible human experience. This account of the source and criterion of knowledge is called empiricism, in distinction from the counter-theory of rationalism.