Sivut kuvina
PDF
ePub

upon as so many established truths : and hence, upon his hypothesis, all real knowledge flows from an internal source, or, in other words, from the mind itself. These ideas can never deceive us, though the senses may do so in their report concerning external objects; and, consequently, such ideas are chiefly to be trusted to and reasoned from even in questions that relate to the senses.

In analysing the idea of thought, the mind, according to Aristotle, discovers it to be a power that has neither extension, figure, local motion, nor any other property commonly ascribed to body. In analysing the idea of God, the mind finds presented to it a being necessarily and eternally existing, supremely intelligent, powerful, and perfect, the fountain of all goodness and truth, and the creator of the universe. In analysing the idea of MATTER, the mind perceives it to be a substance possessing no other property than extent:- or, in other words, as having nothing else belonging to it than length, breadth, and thickness; that space, possessing equally this property, is a part of matter, and, consequently, that matter is universal, and there is no

From these, and other innate ideas, compared and combined with the ideas of sensation, or those furnished to the mind by the senses, flows, on the hypothesis of Des Cartes, the whole fund of human understanding, or all the knowledge that mankind are or can be possessed of.

There are two fundamental errors, and errors, moreover, of an opposite character, that accompany, or rather introduce, this hypothesis, and to which, popular as it was at one time, it has at length completely fallen a sacrifice : these are the attempting

vacuum.

to prove what ought to be taken for granted, and the taking for granted what ought to be proved.

The philosophy of Des Cartes sets.off with supposing that every man is more or less under the influence of prejudice, and, consequently, that he cannot know the real truth of any thing till he has thoroughly sifted it. It follows, necessarily, as a second position, that every man ought, at least once in his life, to doubt of every thing, in order to sift it ; not, however, like the sceptics of Greece, that, by such examination, he may be confirmed in doubt, but that, by obtaining proofs, he may have a settled conviction.

Full fraught with these preliminary principles, our philosopher opens his career of knowledge, and while he himself continues as grave as the noble knight of La Mancha, his journey commences almost as ludicrously. His first doubt is, whether he himself is alive, or in being; and his next, whether any body is alive or in being; about him. He soon satisfies himself, however, upon the first point, by luckily finding out that he thinks, and, therefore, says he gravely, I must be alive:-Cogito ; ergo sum. “I think; therefore I am.” And he almost as soon satisfies himself upon the second, by feeling with his hands about him, and finding out that he can run them against a something or a somebody else, against a man or a post. He then returns home to himself once more, overjoyed with this demonstration of his fingers; and commences a second voyage of discovery by doubting whether he knows any thing besides his own existence, and that of a something beyond him. He then ascertains, to his inexpressible satisfaction, that the soil of his own mind is sown with indigenous ideas precisely like that of thought or consciousness. These he digs up one after another, in order to examine them. One of the first that turns up is that of a God: one of the next is an idea that informs him that the outside of himself, or rather of his mind, is matter; and combining the whole he has thus far acquired with other information obtained from the same sources, he finds that the people whom he has before discovered by means of his hands and eyes call this matter a body, and that the said people have bodies of the same kind, and also of the same kind of knowledge as himself, although not to the same extent or demonstration ; and for this obvious reason, because they have not equally doubted and examined.

It is difficult to be grave upon such a subject. What would be thought or said of any individual in the present audience, who should rise up and openly tell us that he had been long troubled with doubts whether he really existed or not; that his friends had told him he did, and he was inclined to believe 50; but that as this belief might be a mere prejudice, he was at length determined to try the fact by asking himself this plain question,—“ Do I think ?” Is there a person before me but would exclaim, almost instinctively, “Ah! poor creature, he had better ask himself another plain question,- whether he is in his sober senses ?”

If, however, we attempt to examine seriously the mode which Des Cartes thus proposes of following up his own principles, it is impossible not to be astonished at his departure from them at the first outset. Instead of doubting of every thing and proving every thing, the very first position before him he

takes for granted :- “I think; therefore I am.” Of these two positions, he makes the first the proof of the second, but what is the proof of the first? If it be necessary to prove that he is, the very groundwork of his system renders it equally necessary to prove that HE THINKS. But this he does not attempt to do: in direct contradiction to his fundamental principles he here commits a petitio principii, and takes it for granted. I do not find fault with him for taking it for granted; but then he might as well have saved himself the trouble of manufacturing an imperfect syllogism, and have taken it for granted also that he was alive or that he existed, for the last fact must have been just as obvious to himself as the first, and somewhat more so to the world at large.

There is another logical error in this memorable enthymeme, or syllogism without a head, which ought not to pass without notice; I mean that the proof does not run parallel with the predicate, and, consequently, does not answer its purpose. The subject predicated is that the philosopher exists or is alive, and to prove this he affirms gratuitously that he thinks. “I think, and therefore I am.” Now, in respect to the extent or parallelism of the proof, he might just as well have said, “ I itch," or “ I eat, and therefore I am.” I will not dispute that in all probability he thought more than he itched, or partook of food: but let us take which proof we will, it could only be a proof so long as he itched, or was eating; and, consequently, whenever he ceased from either of these conditions, upon his own argument, he would have no proof whatever of being alive. Now, that he must often have ceased

from itching, or eating, there is no difficulty in admitting; but then he may also at times have ceased from thinking, not only in various morbid states of the brain, but whenever he slept without dreaming. And hence, the utmost that any such argument could decide in his favour, let us take which kind of proof we will, would be that he could alternately prove himself to be alive and alternately not alive; that it was obvious to himself that he existed for and during the time that he thought, itched, or ate, but that he had no proof of existence as soon as these were over.

But I have said, that Des Cartes' philosophy consists not only in demanding proofs where no proofs are necessary, and where the truisms are so clear as to render it ludicrous to ask for them, but in taking for granted propositions that evidently demand proof. And I now allude to his whole doctrine of innate ideas — of axioms or principles planted in the mind by the hand of nature herself, and which are evidently intended to supply the place of the intelligible world of Plato and Aristotle.

Of these I have only produced a small sample, and it is not necessary to bring more to market. Let us state his innate idea of a God. It is, I admit, a very reverential, correct, and perfect one, and does him credit as a theologist; but I am not at present debating with him as a theologist, but as a logician. It is, in truth, owing to its very perfection that I object to it; for there is strong ground to suspect, notwithstanding all his care to the contrary, that he has obtained it from induction, rather than from impulse; from an open creed, than from a latent principle. If such an idea be innate to him,

« EdellinenJatka »