ON HUMAN UNDERSTANDING. 



389 



chiefly to be trusted to and reasoned from even in questions that relate to 

 the senses. 



In analyzing the idea of thought, the rnind, 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 analyzing 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 analyzing 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 thctn 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 vacuum. 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 

 fimd 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 hy|)othe&is, and to 

 which, popular as it was at one time, it has at length completely/ fallen a 

 sacrifice : these are the attempting 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 oflf 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 how- 

 ever, like the skeptics 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, whe- 

 ther any body is alive or in being about him. He soon satisfies himself how- 

 ever, upon the first point, by luckily finding out that he thinks, and therefore, 

 says he gravely, I must be afive : Cogito^ ergo sum. " I think, and therefore 

 I am." And he almost as soon satisfies himself upon the second, by feel- 

 ing 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. And he now ascertains, to his inexpressible satis- 

 faction, 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 out- 

 side of himself, or rather of his mind, is matter ; and com.bining the 

 whole he has thus far acquired with other information obtained from the 

 same sources, he finds that the people whom be 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 alsp the same kind of knowledge 



