Now Aristotle understands Plato to have held that universals have objective existence; and indeed Plato had said that the universal is incomparably more lasting and important and substantial than the individual,—the latter being but a little wavelet in a ceaseless surf; men come and go, but man goes on forever. Aristotle’s is a matter-of-fact mind; as William James would say, a tough, not a tender, mind; he sees the root of endless mysticism and scholarly nonsense in this Platonic “realism”; and he attacks it with all the vigor of a first polemic. As Brutus loved not Cæsar less but Rome more, so Aristotle says, Amicus Plato, sed magis amica veritas—“Dear is Plato, but dearer still is truth.”
A hostile commentator might remark that Aristotle (like Nietzsche) criticizes Plato so keenly because he is conscious of having borrowed from him generously; no man is a hero to his debtors. But Aristotle has a healthy attitude, nevertheless; he is a realist almost in the modern sense; he is resolved to concern himself with the objective present, while Plato is absorbed in a subjective future. There was, in the Socratic-Platonic demand for definitions, a tendency away from things and facts to theories and ideas, from particulars to generalities, from science to scholasticism; at last Plato became so devoted to generalities that they began to determine his particulars, so devoted to ideas that they began to define or select his facts. Aristotle preaches a return to things, to the “unwithered face of nature” and reality; he had a lusty preference for the concrete particular, for the flesh and blood individual. But Plato so loved the general and universal that in the Republic he destroyed the individual to make a perfect state.
Yet, as is the usual humor of history, the young warrior takes over many of the qualities of the old master whom he assails. We have always goodly stock in us of that which we condemn: as only similars can be profitably contrasted, so only similar people quarrel, and the bitterest wars are over the slightest variations of purpose or belief. The knightly Crusaders found in Saladin a gentleman with whom they could quarrel amicably; but when the Christians of Europe broke into hostile camps there was no quarter for even the courtliest foe. Aristotle is so ruthless with Plato because there is so much of Plato in him; he too remains a lover of abstractions and generalities, repeatedly betraying the simple fact for some speciously bedizened theory, and compelled to a continuous struggle to conquer his philosophic passion for exploring the empyrean.
There is a heavy trace of this in the most characteristic and original of Aristotle’s contributions to philosophy—the doctrine of the syllogism. A syllogism is a trio of propositions of which the third (the conclusion) follows from the conceded truth of the other two (the “major” and “minor” premisses). E.g., man is a rational animal; but Socrates is a man; therefore Socrates is a rational animal. The mathematical reader will see at once that the structure of the syllogism resembles the proposition that two things equal to the same thing are equal to each other; if A is B, and C is A, then C is B. As in the mathematical case the conclusion is reached by canceling from both premisses their common term, A; so in our syllogism the conclusion is reached by canceling from both premisses their common term “man,” and combining what remains. The difficulty, as logicians have pointed out from the days of Pyrrho to those of Stuart Mill, lies in this, that the major premiss of the syllogism takes for granted precisely the point to be proved; for if Socrates is not rational (and no one questions that he is a man) it is not universally true that man is a rational animal. Aristotle would reply, no doubt, that where an individual is found to have a large number of qualities characteristic of a class (“Socrates is a man”), a strong presumption is established that the individual has the other qualities characteristic of the class (“rationality”). But apparently the syllogism is not a mechanism for the discovery of truth so much as for the clarification of exposition and thought.
All this, like the many other items of the Organon, has its value: “Aristotle has discovered and formulated every canon of theoretical consistency, and every artifice of dialectical debate, with an industry and acuteness which cannot be too highly extolled; and his labors in this direction have perhaps contributed more than any other single writer to the intellectual stimulation of after ages.”14 But no man ever lived who could lift logic to a lofty strain: a guide to correct reasoning is as elevating as a manual of etiquette; we may use it, but it hardly spurs us to nobility. Not even the bravest philosopher would sing to a book of logic underneath the bough. One always feels towards logic as Virgil bade Dante feel towards those who have been damned because of their colorless neutrality: Non ragionam di lor, ma guarda e passa15—“Let us think no more about them, but look once and pass on.”
IV. The Organization of Science
1. GREEK SCIENCE BEFORE ARISTOTLE
“Socrates,” says Renan,16 “gave philosophy to mankind, and Aristotle gave it science. There was philosophy before Socrates, and science before Aristotle; and since Socrates and since Aristotle, philosophy and science have made immense advances. But all has been built upon the foundation which they laid.” Before Aristotle, science was in embryo; with him it was born.
Earlier civilizations than the Greek had made attempts at science; but so far as we can catch their thought through their still obscure cuneiform and hieroglyphic script, their science was indistinguishable from theology. That is to say, these pre-Hellenic peoples explained every obscure operation in nature by some supernatural agency; everywhere there were gods. Apparently it was the Ionian Greeks who first dared to give natural explanations of cosmic complexities and mysterious events: they sought in physics the natural causes of particular incidents, and in philosophy a natural theory of the whole. Thales (640–550 B.C.), the “Father of Philosophy,” was primarily an astronomer, who astonished the natives of Miletus by informing them that the sun and stars (which they were wont to worship as gods) were merely balls of fire. His pupil Anaximander (610–540 B.C.), the first Greek to make astronomical and geographical charts, believed that the universe had begun as an undifferentiated mass, from which all things had arisen by the separation of opposites; that astronomic history periodically repeated itself in the evolution and dissolution of an infinite number of worlds; that the earth was at rest in space by a balance of internal impulsions (like Buridan’s ass); that all our planets had once been fluid, but had been evaporated by the sun; that life had first been formed in the sea, but had been driven upon the land by the subsidence of the water; that of these stranded animals some had developed the capacity to breathe air, and had so become the progenitors of all later land life; that man could not from the beginning have been what he now was, for if man, on his first appearance, had been so helpless at birth, and had required so long an adolescence, as in these later days, he could not possibly have survived. Anaximenes, another Milesian (fl. 450 B.C.), described the primeval condition of things as a very rarefied mass, gradually condensing into wind, cloud, water, earth, and stone; the three forms of matter—gas, liquid and solid—were progressive stages of condensation; heat and cold were merely rarefaction and condensation; earthquakes were due to the solidification of an originally fluid earth; life and soul were one, an animating and expansive force present in everything everywhere. Anaxagoras (500–428 B.C.), teacher of Pericles, seems to have given a correct explanation of solar and lunar eclipses; he discovered the processes of respiration in plants and fishes; and he explained man’s intelligence by the power of manipulation that came when the fore-limbs were freed from the tasks of locomotion. Slowly, in these men, knowledge grew into science.