« ForrigeFortsæt »
HISTORY OF MAN.
A BRIEF ACCOUNT OF ARISTOTLE'S LOGIC,
N reviewing the foregoing sketch, it occurred,
that a fair analysis of Aristotle's logic, would be a valuable addition to the historical branch. A distinct and candid account of a system that for many ages governed the reasoning part of mankind, cannot but be acceptable to the public. Curiosity will be gratified, in seeing a phantom delineated that so long fascinated the learned world; a phantom, which shows infinite genius, but like
the pyramids of Egypt or hanging gardens of Babylon, is absolutely useless unless for raising wonder. Dr Reid, professor of moral philosophy in the College of Glasgow, relished the thought; and his friendship to me prevailed on him, after much solicitation, to undertake the laborious task. No man is better acquainted with Aristotle's writings ; and, without any enthusiastic attachment, he holds that philosopher to be a first-rate genius.
The logic of Aristotle has been on the decline more than a century; and is at present relegated to schools and colleges. It has occasionally been criticised by different writers; but this is the first attempt to draw it out of its obscurity into daylight. From what follows, one will be enabled to pass a true judgment on that work, and to determine whether it ought to make a branch of education. The Doctor's essay, as a capital article in the progress and history of the sciences, will be made welcome, even with the fatigue of squeezing through many thorny paths, before a distinct view can be got of that ancient and stupendous fabric.
It will at the same time show the hurt that Aristotle has done to the reasoning faculty, by drawing it out of its natural course into devious paths. His artificial mode of reasoning, is no less superficial than intricate : I say, superficial; for in none of his logical works, is a single truth attempted to be proved by syllogism that requires a 'proof: the
propositions he undertakes to prove by syllogism, are all of them self-evident. Take for instance the following proposition, That man has a power of self-motion. To prove this, he assumes the following axiom, upon which indeed every one of his syllogisms are founded, That whatever is true of a number of particulars joined together, holds true of every one separately ; which is thus expressed in logical terms, Whatever is true of the genus, holds true of every species. Founding upon that axiom, he reasons thus : “ All animals have a
power of self-motion : man is an animal: ergo,
man has a power of self-motion.” Now, if all animals have a power of self motion, it requires no argument to prove, that man, an animal, has that power : and therefore, what he gives as a conclusion or consequence is not really so ; it is not inferred from the fundamental proposition, but is included in it. At the same time, the self-motive power of man, is a fact that cannot be known but from experience; and it is more clearly known from experience than that of any other animal. Now, in attempting to prove man to be a self-motive animal, is it not absurd, to found the argument on a proposition less clear than that undertaken to be demonstrated ? What is here observed, will be found applicable to the greater part, if not the whole of his syllogisms.
Unless for the reason now given, it would appear singular, that Aristotle never attempts to apply A 2