Aristotle was the father of logic, and Hegel and Kant think there has been no improvement upon it since his day.  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 processes of thought.  Induction and syllogism are the two great features of his system of 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, the whole evincing much ingenuity and skill in construction, and presenting at the same time a useful 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.  Thus Aristotle made speculation subordinate to logical distinctions, and his system, when carried out by the mediaeval Schoolmen, led to a spirit of useless quibbling.  Instead of interrogating Nature they interrogated their own minds, and no great discoveries were made.  From want of proper knowledge of the conditions of scientific inquiry, the method of Aristotle became fruitless for him; but it was the key by which future investigators were enabled to classify and utilize their vastly greater collection of facts and materials.

Though Aristotle wrote in a methodical manner, his writings exhibit 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.

Philosophy, as a great system of dialectics, as an analysis of the power and faculties of the mind, as a method to pursue inquiries, 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 Sceptics, like Pyrrho, had only negative doctrines, and held in disdain 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.  They pointed out the uncertainty of things, and the folly of striving to comprehend them.