Quotes About Certainty

For the very fact that my knowledge is increasing little by little is the most certain argument for its imperfection.

And what more am I? I look for aid to the imagination. [But how mistakenly!] I am not that assemblage of limbs we call the human body; I am not a subtle penetrating air distributed throughout all these members; I am not a wind, a fire, a vapor, a breath or anything at all that I can image. I am supposing all these things to be nothing. Yet I find, while so doing, that I am still assured that I am a something.

The first was never to accept anything for true which I did not clearly know to be such; that is to say, carefully to avoid precipitancy and prejudice, and to comprise nothing more in my judgment than what was presented to my mind so clearly and distinctly as to exclude all ground of doubt.

When it is not in our power to determine what it true, we ought to follow what is most probable.

I took especially great pleasure in mathematics because of the certainty and the evidence of its arguments.

I am not a collection of members which we call the human body: I am not a subtle air distributed through these members, I am not a wind, a fire, a vapour, a breath, nor anything at all which I can imagine or conceive; because I have assumed that all these were nothing. Without changing that supposition I find that I only leave myself certain of the fact that I am somewhat.

The first precept was never to accept a thing as true until I knew it as such without a single doubt

Je pense, donc je suis; English: I think, therefore I am)

To think? That's it. It is thought. This alone cannot be detached from me. I am, I exist; that is certain.

All that I have, up to this moment, accepted as possessed of the highest truth and certainty, I received either from or through the senses. I observed, however, that these sometimes misled us; and it is the part of prudence not to place absolute confidence in that by which we have even once been deceived.

we ought not meanwhile to make use of doubt in the conduct of life.

Finally, if there be still persons who are not sufficiently persuaded of the existence of God and of the soul, by the reasons I have adduced, I am desirous that they should know that all the other propositions, of the truth of which they deem themselves perhaps more assured, as that we have a body, and that there exist stars and an earth, and such like, are less certain;

For there is hardly any question in the sciences about which clever men have not frequently disagreed. But whenever two persons make opposite judgements about the same thing, it is certain that at least one of them is mistaken, and neither, it seems, has knowledge. For if the reasoning of one of them were certain and evident, he would be able to lay it before the other in such a way as eventually to convince his intellect as well.

I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.

I had always a most earnest desire to know how to distinguish the true from the false, in order that I might be able clearly to discriminate the right path in life, and proceed it in with confidence.

I will follow this strategy until I discover something that is certain or, at least, until I discover that it is certain only that nothing is certain.

It is enough that I can understand one thing, clearly and distinctly, without another in order to be certain that one thing is distinct from the other.

If I find some reason for doubt in each of my beliefs, that will be enough to reject all of them.

Je puis me persuader d'avoir été fait tel par la nature que je puisse aisément me tromper même dans les choses que je crois comprendre avec le plus d'évidence et de certitude.

One needs to know what thought is, what existence is and what certainty is.

was most keen on mathematics, because of its certainty and the incontrovertibility* of its proofs; but I did not yet see its true use. Believing as I did that its only application was to the mechanical arts,* I was astonished that nothing more exalted had been built on such sure and solid foundations; whereas, on the other hand, I compared the moral works of ancient pagan writers to splendid and magnificent palaces built on nothing more than sand and mud.

we ought also to consider as false all that is doubtful.

while I wanted thus to think that everything was false, it necessarily had to be the case that I, who was thinking this, was something. And noticing that this truth—I think, therefore I am—was so firm and so assured that all the most extravagant suppositions of the skeptics were incapable of shaking it, I judged that I could accept it without scruple as the first principle of the philosophy I was seeking.

c'est une vérité très certaine que, lorsqu'il n'est pas en notre pouvoir de discerner les plus vraies opinions, nous devons suivre les plus probables partie 3, para 3)