It is not enough to have a good mind. The main thing is to use it well.

In order to improve the mind, we ought less to learn, than to contemplate.

[About Pierre de Fermat] It cannot be denied that he has had many exceptional ideas, and that he is a highly intelligent man. For my part, however, I have always been taught to take a broad overview of things, in order to be able to deduce from them general rules, which might be applicable elsewhere.

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

I have concluded the evident existence of God, and that my existence depends entirely on God in all the moments of my life, that I do not think that the human spirit may know anything with greater evidence and certitude.

There is nothing so strange and so unbelievable that it has not been said by one philosopher or another.

For to be possessed of a vigorous mind is not enough; the prime requisite is rightly to apply it.