With Aristotle, ethics formed only one branch of his attention. His main inquiries were in reference to physics and metaphysics. He thus, by bringing these into the region or inquiry, paved the way for a new epoch of skepticism. [Footnote: Lewes, Ritter, Hegel, Maurice, Diogenes Laertius. See fine article in Encyclopedia Britannica. Schwegler, translated by Seelyn.]
It is impossible, within the proper limits of this chapter, to enter upon an analysis of the philosophy of either the three great lights of the ancient world, or to enumerate and describe their other writings. I merely wish to show what are considered to be the vital principles on which their systems were based, and the general spirit of their speculations. The student must examine these in the elaborate treatises of modern philosophers, and in the original works of Plato and Aristotle.
[Sidenote: Their characteristic inquiries.]
Both Plato and Aristotle taught that reason alone could form science; but Aristotle differed from his master respecting the theory of ideas. He did not deny to ideas a subjective existence, but he did deny that they have an objective existence. And he maintained that the individual things alone existed, and if individuals only exist, they can only be known by sensation. Sensation thus becomes the basis of knowledge. Plato made reason the basis of knowledge, but Aristotle made experience. Plato directed man to the contemplation of ideas; Aristotle, to the observations of Nature. Instead of proceeding synthetically and dialectically like Plato, he pursues an analytic course. His method is hence inductive—the derivation of certain principles from a sum of given facts and phenomena. It would seem that positive science commenced with him, since he maintained that experience furnishes the principles of every science; but, while his conception was just, there was not sufficient experience then accumulated from which to generalize with effect. He did not sufficiently verify his premises. His reasoning was correct upon the data given, as in the famous syllogism, "All black birds are crows; this bird is black; therefore this bird is a crow." The defect of the syllogism is not in the reasoning, but in the truth of the major premise, since all black birds are not crows. It is only a most extensive and exhaustive examination of the accuracy of a proposition which will warrant reasoning upon it. Aristotle reasoned without sufficient examination of the major premise of his syllogisms.
[Sidenote: Logic of Aristotle.]
Aristotle was the father of logic, and Hegel and Kant think there has been no improvement upon it since his day. And this became to him the real organon of science. "He supposed it was not merely the instrument of thought, but the instrument of investigation." Hence it was futile for purposes of discovery, although important to aid the processes of thought. Induction and syllogism are the two great instruments of his logic. The one sets out from particulars already known to arrive at a conclusion; the other sets out from some general principle to arrive at particulars. The latter more particularly characterized his logic, which he presented in sixteen forms, showing great ingenuity, and useful as a dialectical exercise. This syllogistic process of reasoning would be incontrovertible, if the general were better known than the particular. But it is only by induction, which proceeds from the world of experience, that we reach the higher world of cognition. We arrive at no new knowledge by the syllogism, since the major premise is more evident than the conclusion, and anterior to it. Thus he made speculation subordinate to logical distinctions, and his system, when carried out by the schoolmen, led to a spirit of useless quibbling. Instead of interrogating Nature, as Bacon led the way, they interrogated their own minds, and no great discoveries were made. From a want of a proper knowledge of the conditions of scientific inquiry, the method of Aristotle became fruitless. [Footnote: Maurice, Anc. Phil. See Whewell, Hist. Ind. Science.]
Though Aristotle wrote in a methodical manner, yet there is great parsimony of language. There is no fascination in his style. It is without ornament, and very condensed. His merit consisted in great logical precision, and scrupulous exactness in the employment of terms.
[Sidenote: The Skeptics.]
Philosophy, as a great system of dialectics, as an analysis of the power and faculties of the mind, as a method to pursue inquiries, as an intellectual system merely, culminated in Aristotle. He completed the great fabric of which Thales laid the foundation. The subsequent schools of philosophy directed attention to ethical and practical questions, rather than to intellectual phenomena. The skeptics, like Pyrrho, had only negative doctrines, and had a disdain of those inquiries which sought to penetrate the mysteries of existence. They did not believe that absolute truth was attainable by man. And they attacked the prevailing systems with great plausibility. Thus Sextus attacked both induction and definitions. "If we do not know the thing we define," said he, "we do not comprehend it because of the definition, but we impose on it the definition because we know it; and if we are ignorant of the thing we would define, it is impossible to define it." Thus the skeptics pointed out the uncertainty of things and the folly of striving to comprehend them.
The Epicureans despised the investigations of philosophy, since, in their view, they did not contribute to happiness. The subject of their inquiries was happiness, not truth. What will promote this, was the subject of their speculation. Epicurus, born B.C. 342, contended that pleasure was happiness; that pleasure should not be sought for its own sake, but with a view of the happiness of life obtained by it. He taught that it was inseparable from virtue, and that its enjoyments should be limited. He was averse to costly pleasures, and regarded contentedness with a little to be a great good. He placed wealth not in great possessions, but few wants. He sought to widen the domain of pleasure, and narrow that of pain, and regarded a passionless state of life the highest. Nor did he dread death, which was deliverance from misery. Epicurus has been much misunderstood, and his doctrines were subsequently perverted, especially when the arts of life were brought into the service of luxury, and a gross materialism was the great feature of society. Epicurus had much of the practical spirit of a philosopher, although very little of the earnest cravings of a religious man. He himself led a virtuous life, because it was wiser and better to be virtuous, not because it was his duty. His writings were very voluminous, and in his tranquil garden he led a peaceful life of study and enjoyment. His followers, and they were numerous, were led into luxury and effeminacy, as was to be expected from a skeptical and irreligious philosophy, the great principle of which was that whatever is pleasant should be the object of existence. [Footnote: the doctrines of the Epicureans are best set forth in Lucretius.]