The rationalistic motive was a quickening influence in Greek philosophy long before it became deliberate and conspicuous in Socrates and Plato. Parmenides, founder of the Eleatic School, has left behind him a poem divided into two parts: "The Way of Truth" and "The Way of Opinion."[168:14] In the first of these he expounds his esoteric philosophy, which is a definition of being established by dialectical reasoning. He finds that being must be single, eternal, and changeless, because otherwise it cannot be thought and defined without contradiction. The method which Parmenides here employs presupposes that knowledge consists in understanding rather than perception. Indeed, he regards the fact that the world of the senses is manifold and mutable as of little consequence to the wise man. The world of sense is the province of vulgar opinion, while that of reason is the absolute truth revealed only to the philosopher. The truth has no concern with appearance, but is answerable only to the test of rationality. That world is real which one is able by thinking to make intelligible. The world is what a world must be in order to be possible at all, and the philosopher can deduce it directly from the very conditions of thought which it must satisfy. He who would know reality may disregard what seems to be, provided he can by reflective analysis discover certain general necessities to which being must conform. This is rationalism in its extreme form.
The rationalism of Socrates was more moderate, as it was more fruitful than that of Parmenides. As is well known, Socrates composed no philosophical books, but sought to inculcate wisdom in his teaching and conversation. His method of inculcating wisdom was to evoke it in his interlocutor by making him considerate of the meaning of his speech. Through his own questions he sought to arouse the questioning spirit, which should weigh the import of words, and be satisfied with nothing short of a definite and consistent judgment. In the Platonic dialogues the Socratic method obtains a place in literature. In the "Theætetus," which is, perhaps, the greatest of all epistemological treatises, Socrates is represented as likening his vocation to that of the midwife.
"Well, my art of midwifery is in most respects like theirs, but differs in that I attend men, and not women, and I look after their souls when they are in labor, and not after their bodies: and the triumph of my art is in thoroughly examining whether the thought which the mind of the young man brings forth is a false idol or a noble and true birth. And, like the midwives, I am barren, and the reproach which is often made against me, that I ask questions of others and have not the wit to answer them myself, is very just; the reason is that the god compels me to be a midwife, but does not allow me to bring forth. And therefore I am not myself at all wise, nor have I anything to show which is the invention or birth of my own soul, but those who converse with me profit. . . . It is quite clear that they never learned anything from me; the many fine discoveries to which they cling are of their own making."[171:15]
The principle underlying this method is the insistence that a proposition, to be true of reality, must at least bespeak a mind that is true to itself, internally luminous, and free from contradiction. That which is to me nothing that I can express in form that will convey precise meaning and bear analysis, is so far nothing at all. Being is not, as the empiricist would have it, ready at hand, ours for the looking, but is the fruit of critical reflection. Only reason, overcoming the relativity of perception, and the chaos of popular opinion, can lay hold on the universal truth.
A very interesting tendency to clothe the articulations of thought with the immediacy of perception is exhibited in mysticism, which attributes the highest cognitive power to an experience that transcends thought, an ineffable insight that is the occasional reward of thought and virtuous living. This theory would seem to owe its great vigor to the fact that it promises to unite the universality of the rational object with the vivid presence of the empirical object, though it sacrifices the definite content of both. The mystic, empiricist, and rationalist are in these several ways led to revise their metaphysics upon the basis of their epistemology, or to define reality in terms dictated by the means of knowing it.
The Relation of Knowledge to its Object According to Realism, and the Representative Theory.
§ [69]. But within the general field of epistemology there has arisen another issue of even greater significance in its bearing upon metaphysics. The first issue, as we have seen, has reference to the criterion of knowledge, to the possibility of arriving at certainty about reality, and the choice of means to that end. A second question arises, concerning the relation between the knowledge and its object or that which is known. This problem does not at first appear as an epistemological difficulty, but is due to the emphasis which the moral and religious interests of men give to the conception of the self. My knowing is a part of me, a function of that soul whose welfare and eternal happiness I am seeking to secure. Indeed, my knowing is, so the wise men have always taught, the greatest of my prerogatives. Wisdom appertains to the philosopher, as folly to the fool. But though my knowledge be a part of me, and in me, the same cannot, lightly at any rate, be said of what I know. It would seem that I must distinguish between the knowledge, which is my act or state, an event in my life, and the known, which is object, and belongs to the context of the outer world. The object of knowledge would then be quite independent of the circumstance that I know it. This theory has acquired the name of realism,[173:16] and is evidently as close to common sense as any epistemological doctrine can be said to be. If the knowledge consists in some sign or symbol which in my mind stands for the object, but is quite other than the object, realism is given the form known as the representative theory. This theory is due to a radical distinction between the inner world of consciousness and the outer world of things, whereby in knowledge the outer object requires a substitute that is qualified to belong to the inner world. Where, on the other hand, no specific and exclusive nature is attributed to the inner world, realism may flourish without the representative theory. In such a case the object would be regarded as itself capable of entering into any number of individual experiences or of remaining outside them all, and without on either account forfeiting its identity. This view was taken for granted by Plato, but is elaborately defended in our own day. During the intervening period epistemology has been largely occupied with difficulties inherent in the representative theory, and from that discussion there has emerged the theory of idealism,[175:17] the great rival theory to that of realism.
The Relation of Knowledge to its Object According to Idealism.
§ [70]. The representative theory contains at least one obvious difficulty. If the thinker be confined to his ideas, and if the reality be at the same time beyond these ideas, how can he ever verify their report? Indeed, what can it mean that an idea should be true of that which belongs to a wholly different category? How under such circumstances can that which is a part of the idea be attributed with any certainty to the object? Once grant that you know only your ideas, and the object reduces to an unknown x, which you retain to account for the outward pointing or reference of the ideas, but which is not missed if neglected. The obvious though radical theory of idealism is almost inevitably the next step. Why assume that there is any object other than the state of mind, since all positive content belongs to that realm? The eighteenth century English philosopher, Bishop Berkeley, was accused by his contemporaries of wilful eccentricity, and even madness, for his boldness in accepting this argument and drawing this conclusion:
