I do not know whether I should tell you about the first meditations I made there, for they are so metaphysical and so uncommon that they may not suit everyone's taste. And yet, so that I might judge whether the foundations I had chosen were firm enough, I find myself in a way compelled to speak of them.

I had by then observed that, in order to conduct my reason well and seek truth in the sciences, there was first a need for method, and that this method could be sought only in the mathematics. But since our soul, while it is in this body, is as it were asleep amid the slumber of our passions, I resolved to set aside all the opinions I had received until then, in order to examine their foundations afterward.

For although, in doing so, there appeared to be no occasion for doubting them, I had observed that the things we receive through custom and example are always easier to believe than to know, and that, since we were children before we were men, and had now reason, now appetite, now the opinions of our teachers, it was almost impossible that our judgments should have been as pure and solid as they would have been had we had the full use of our reason from the moment of our birth.

But as I wished to live with as much tranquility as possible, I took care, in the actions of my life, to follow what was most ordinary, and while I thus rejected everything in which I could have the least doubt, I did not fail to follow those opinions that seemed to me most true for the conduct of my life.

What I noticed first is that I doubt, and that, because I doubt, I cannot doubt that I am. Yet that I am, this I knew with a certainty so certain and so evident that, even supposing I had no body, that the world did not exist, that there was no place or time where I was, I could not for all that suppose that I did not exist. On the contrary, from the very fact that I doubted other things, it followed very evidently and very certainly that I was; whereas, had I merely ceased to think, even though all the other things I had ever imagined had been true, I would have had no reason to believe that I had existed.

From this I knew that I was a substance whose whole essence or nature is only to think, and which, in order to be, has no need of place and does not depend on any material thing. So that this me, that is to say the soul by which I am what I am, is entirely distinct from the body, and is even easier to know than it, and would not cease to be all that it is even if the body did not exist.

After that I considered in general what is required of a proposition to be true and certain; for since I had just found one that I knew to be such, I thought I should also know wherein this certainty consists. And having remarked that there is nothing at all in 'I think, therefore I am' that assures me of speaking the truth, except that I see very clearly and very evidently that to think one must be, I judged that I could take as a general rule that the things we conceive very clearly and very distinctly are all true.

Then, reflecting upon the fact that I doubted, and that consequently my being was not wholly perfect, for I saw clearly that it is a greater perfection to know than to doubt, I asked myself whence I had learned to think of something more perfect than myself; and I knew very evidently that this must come from some nature that was in fact more perfect than mine. And having remarked that I had in me the thought of something more perfect than myself, I recognized that this nature had to be God. For although the idea of a substance is in me by the very fact that I am a substance, I would not nevertheless have the idea of an infinite substance, I who am a finite being, unless it had been placed in me by some substance that was truly infinite.