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

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

If I found any new truths in the sciences, I can say that they follow from, or depend on, five or six principal problems which I succeeded in solving and which I regard as so many battles where the fortunes of war were on my side.

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

The two operations of our understanding, intuition and deduction, on which alone we have said we must rely in the acquisition of knowledge.

Common sense is the most fairly distributed thing in the world, for each one thinks he is so well-endowed with it that even those who are hardest to satisfy in all other matters are not in the habit of desiring more of it than they already have.