Logic. Though various definitions have been given of this pursuit, there is now, I suppose, a pretty general tendency to acquiesce in that of Sir W. Hamilton. Pure logic according to him is «the science of formal thought» or «the science of the form of thought,» therefore the science of the λόγος. It may also be called in a more limited view the science of science, any branch of knowledge rising to the dignity of a science when it is conformed to logical laws. Applied or mixed logic of course touches on many collateral subject.
The study is as might be expected an ancient one. The Hindoos have cultivated it for a period probably of two thousand years if not more, their great luminary on the subject being a certain Gotama, about whose era we are in ignorance. It was with the Geeks, however, that the pursuit took the form which it has retained among Arabs, Jews, and Christians ever since; nor is there any reason to suppose that they were indebted to India for its acquisition.
From the very nature of its subject, logic is a science that might well arise spontaneously in any community at once cultivated and acute; and the Hindoo logic, if we are to take Gotama for its interpreter, is so different from the Aristotelian, that the two must be considered independent growths. Zeno the Eleatic has been often spoken of as the founder of the Greek logic. Socrates and Plato were masters of it so far as division and definition rank among its essential parts. But Aristotle gave it the complete shape which it has worn ever since. Though this be so, he has neither denned it, nor bestowed on it the name logic, or indeed any one name, though he uses the adjective λογικός, and the adverb λογικῶς. The works of his in which the system is unfolded are now collectively styled the Organon, instrument, but this title is modern. They are as follows: 1st, the Categories; 2ndly, the treatise de Interpretatione;(1) 3rdly, the two books of Prior, and 4thly, the two of Posterior Analytics; 5thly, the eight books of Topics; and 6thly, the single book on Sophistici Elenchi. Allied to these, though not included in the Organon, is the treatise on Rhetoric. Moreover, as might be expected, applications of his logical method are to be met with in great abundance throughout Aristotle’s works. It is impossible to say when the title logic, λογική (properly an adjective τέχνη, ἐπιστήμη, or πραγματεία being understood), first came into use. It is found in the writings of Alexander of Aphrodisias, a commentator on Aristotle who lived in the second century, and it is said by Boëthius to have been introduced by the ancient Peripatetics.(2) It needs scarcely be said that it has established itself for ages, and has served to mark off logic from the other branches of mental science, such as psychology and metaphysics.
It is beside my purpose to trace the history of this science. It is generally known that the works of Aristotle were communicated to Western Europe by the Arabians, and read in Latin translations, and that logic after a time became sovereign of the schools. Devoted, however, though they were to the study, the schoolmen added little but some nice distinctions to its substance as bequeathed by Aristotle. But they enriched it with a most copious and felicitous terminology, and by formulating its leading principles in mnemonic verses.
At the termination of the scholastic period, the reaction as to logic took two directions, one that of trying to reform and improve the science, the other that of neglecting and despising it. The efforts in the former of these, though made by men of great talents and influence, such as Ramus, led to nothing permanent. The neglect and contempt were but partial in their extent, Germany having never countenanced them, and must be considered to have on the whole passed away, a great reaction on the subject having taken place among ourselves, and many valuable logical works having been produced by some of our most distinguished men. Probably the last person of consequence who has ventured to speak of logic in the tone, of Locke, Stewart, and Brown, was the late Lord Macaulay, in a well-known passage in his brilliant but most untrustworthy essay on Bacon. The reader who has been allured by it (the passage in question) should betake himself to Professor De Morgan’s demolishing reply, which is nearly as witty as the sophistry which it crushed.(3)
It is worthy too of remark that not only is the present age rich in logical works, but that it has seen the science itself enlarged and deepened, eminently by Sir W. Hamilton and Mr. Stanley Jevons.
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(1) The genuineness of these two books has been questioned.
(2) HAMILTON, Logic, Les. I. pp. 4, 5.
(3) DE MORGAN, Formal Logic, pp. 216-224.
