The World's Greatest Books [Volumes 1-15, 17-20]

IV.--"I Think, Therefore I Am"

I had long since remarked that in matters of conduct it is necessary sometimes to follow opinions known to be uncertain, as if they were not subject to doubt; but, because now I was desirous to devote myself to the search after truth, I considered that I must do just the contrary, and reject as absolutely false everything concerning which I could imagine the least doubt to exist.

Thus, because our senses sometimes deceive us I would suppose that nothing is such as they make us to imagine it; and because I was as likely to err as another in reasoning, I rejected as false all the reasons which I had formerly accepted as demonstrative; and finally, considering that all the thoughts we have when awake can come to us also when we sleep without any of them being true, I resolved to feign that everything which had ever entered into my mind was no more truth than the illusion of my dreams.

But I observed that, while I was thus resolved to feign that everything was false, I who thought must of necessity be somewhat; and remarking this truth--"I think, therefore I am"--was so firm and so assured that all the most extravagant suppositions of the sceptics were unable to shake it, I judged that I could unhesitatingly accept it as the first principle of the philosophy I was seeking. I could feign that there was no world, I could not feign that I did not exist. And I judged that I might take it as a general rule that the things which we conceive very clearly and very distinctly are all true, and that the only difficulty lies in the way of discerning which those things are that we conceive distinctly.

After this, reflecting upon the fact that I doubted, and that consequently my being was not quite perfected (for I saw that to know is a greater perfection than to doubt), I bethought me to inquire whence I had learned to think of something more perfect than myself; and it was clearto me that this must come from some nature which was in fact more perfect. For other things I could regard as dependencies of my nature if they were real, and if they were not real they might proceed from nothing--that is to say, they might exist in me by way of defect. But it could not be the same with the idea of a being more perfect than my own; for to derive it from nothing was manifestly impossible; and, because it is no less repugnant that the more perfect should follow and depend upon the less perfect than that something should come forth out of nothing, I could not derive it from myself.

It remained, then, to conclude that it was put into me by a nature truly more perfect than was I, and possessing in itself all the perfections of what I could form an idea--in a word, by God. To which I added that, since I knew some perfections which I did not possess, I was not the only being who existed, but that there must of necessity be some other being, more perfect, on whom I depended, and from whom I had acquired all that I possessed; for if I had existed alone and independent of all other, so that I had of myself all this little whereby I participated in the Perfect Being, I should have been able to have in myself all those other qualities which I knew myself to lack, and so to be infinite, eternal, immutable, omniscient, almighty--in fine, to possess all the perfections which I could observe in God.

Proposing to myself the geometer's subject matter, and then turning again to examine my idea of a Perfect Being, I found that existence was comprehended in that idea just as, in the idea of a triangle is comprehended the notion that the sum of its angles is equal to two right angles; and that consequently it is as certain that God, this Perfect Being, is or exists, as any geometrical demonstration could be.

That there are many who persuade themselves that there is a difficulty in knowing Him is due to the scholastic maxim that there is nothing in the understandingwhich has not first been in the senses; where the ideas of God and the soul have never been.

Than the existence of God all other things, even those which it seems to a man extravagant to doubt, such as his having a body, are less certain. Nor is there any reason sufficient to remove such doubt but such as presupposes the existence of God. From His existence it follows that our ideas or notions, being real things, and coming from God, cannot but be true in so far as they are clear and distinct. In so far as they contain falsity, they are confused and obscure, there is in them an element of mere negation (elles participent du néant); that is to say, they are thus confused in us because we ourselves are not all perfect. And it is evident that falsity or imperfection can no more come forth from God than can perfection proceed from nothingness. But, did we not know that all which is in us of the real and the true comes from a perfect and infinite being, however clear and distinct our ideas might be, we should have no reason for assurance that they possessed the final perfection--truth.