Conclusion of Book 1

I have uncovered the general errors into which our senses lead us, both regarding their own objects and regarding things that can be perceived only by the understanding; and I do not believe that, by following their reports, we fall into any error whose cause cannot be recognized from what we have just said, provided one is willing to meditate on it a little.

Our senses are given to us only for our body

Our senses are very faithful and very exact in instructing us about the relationships that all bodies surrounding us have with our own, but that they are incapable of teaching us what these bodies are in themselves; that, to make good use of them, one must employ them only to preserve one’s health and life, and that one cannot despise them enough when they seek to rise up and subject the mind. This is the principal thing I wish to be well retained from this entire first book. Let one clearly conceive that our senses are given to us only for the preservation of our body; let one strengthen oneself in this thought, and, to deliver oneself from the ignorance in which one finds oneself, let one seek other aids than those they provide.

We must doubt what they report to us

If there are some persons—and undoubtedly there will be more than enough—who are not persuaded of these last propositions by what has been said thus far, even less is asked of them. It suffices that they enter into some distrust of their senses; and if they cannot entirely reject their reports as false and deceptive, we ask only that they seriously doubt whether these reports are entirely true.

And truly, it seems to me that enough has been said to cast at least some scruple into the minds of reasonable persons, and consequently to excite them to use their liberty differently than they have done until now; for if they can enter into some doubt that the reports of their senses are true, they will also have greater facility in withholding their consent, and thus preventing themselves from falling into the errors into which they have fallen hitherto, principally if they remember the rule at the beginning of this treatise: that one ought never to give full consent except to things that appear entirely evident, and to which one cannot abstain from consenting without recognizing with entire certainty that one would make bad use of one’s liberty by not yielding to them.

It is no small thing to doubt as one ought

Moreover, let one not imagine having made little progress if one has only learned to doubt. Knowing how to doubt with mind and reason is not such a small thing as one thinks; for, it must be said here, there is a great difference between doubting and doubting. One doubts out of impetuosity and brutality, out of blindness and malice; and finally, out of whim, and because one wants to doubt. But one also doubts out of prudence and distrust, out of wisdom and penetration of mind. The Academics and the atheists doubt in the first manner; true philosophers doubt in the second: the first doubt is a doubt of darkness, which leads not to light, but always distances one from it; the second is supported by light, and it helps in some way to produce light in its turn.

Those who doubt only in the first way do not understand what it is to doubt with mind; they mock what Mr. Descartes teaches about doubting in the first of his Metaphysical Meditations, because it seems to them that one need only doubt by whim, and that it suffices to say in general that our nature is infirm; that our mind is full of blindness; that one must take great care to rid oneself of prejudices, and other similar things. They think that this suffices to no longer allow oneself to be seduced by one’s senses and to no longer be mistaken at all. It is not enough to say that the mind is weak; one must make it feel its weaknesses. It is not enough to say that it is subject to error; one must discover to it in what its errors consist. This is what we believe we have begun to do in this first book, by explaining the nature and errors of our senses; and we shall pursue our same design, by explaining in the second book the nature and errors of our imagination.