Logic in the Middle Ages.—It was in the middle ages, however, that logic received its chief cultivation and its highest honors. Aristotle was for some six centuries almost the only teacher of the human mind, and the Organon was the foundation of his knowledge. Nor during the irruption of the northern hordes, and the revolutions of society, and empire, and human manners, which followed, did the philosophy and logic of Aristotle pass out of sight or out of mind. It seemed impossible for any revolution of empire or of time to shake its foundations or break its sceptre over the human mind. In the seventh century, Isidore of Seville, and Bede the Venerable, gave it their labors and renown. In the eighth, Alcuin introduced it into the court of Charlemagne. In the twelfth, Abelard, and the controversy between the Realists and Nominalists, gave this science still more importance.
Logic in the Arabian Schools.—Meanwhile, the Mohammedans had been in advance of the Christians in the study of this science. The Arabs had inherited the learning of antiquity, and had carried the cultivation of the peripatetic philosophy to a high degree of perfection more than a century before it had received the homage of the West. From Arabia it passed, with the march of conquest, into Spain, and some of the ablest commentators Europe has produced, on the works of Aristotle, have been the Moors of Spain.
Continuance of Aristotle's Dominion.—The Crusades tended only to enlarge the sphere of this influence. Such men as Albert the Great, and Thomas Aquinas, became, in the thirteenth century, expounders of Aristotle. Not till the sixteenth century did this long dominion over the human mind show symptoms of decadence.
The Reformers.—Luther, among the Protestant reformers, sought to banish logic from the schools; but it was retained, and in the Protestant universities was still professed.
Attacks upon Aristotle.—It now became the fashion, however, in certain quarters, especially among the mystics in the Catholic communion, to decry Aristotle, and each original genius took this way to show his independence. Ramus is noted among these. Bacon followed in this track, and did little more than repeat the invectives of his predecessors. He attempted to set aside the syllogism, and put in its place induction.
Induction, however, in some form, is as old as the syllogism. From Plato and Aristotle downward, a thousand philosophers had availed themselves of this method of reasoning and had also stated and defended it.
The Moderns.—From Bacon and Descartes till our day logic has been in process of decadence. Locke condemns it. Reid and the Scotch school ridicule its pretensions. Kant and Hegel, on the other hand, give it a due place in their systems—the latter especially; while in France, it has admirers in St. Hilaire, Cousin, and others of like genius; and in Edinburgh, the great Hamilton devoted to it the powers of his unrivalled intellect.
Logic of Hamilton.—As no writer, since the days of Aristotle, has done more to complete and perfect the science of reasoning, than Sir William Hamilton, it seems due that even so brief a sketch of the history of logic as the present, should indicate, at least, the more important changes which his system introduces. Whatever may be thought of some of his views and proposed reforms in this ancient science and sanctuary of past learning, it is not too much to say, that no writer on logic can henceforth present a claim to be considered, who has not, at least, thoroughly mastered and carefully weighed these views and proposed changes, even if he do not adopt them. They are, moreover, for the most part, changes so obviously demanded in order to the completeness of the science, and so thorough-going withal, that they are destined, it would seem, to be sooner or later adopted, and if adopted, to work a radical change in the whole structure of this ancient and time-honored science.
I shall attempt nothing more, in this connection, than, in the briefest manner, to enumerate some of the more important of these improvements.