For each of us there is a set limit to our intellectual powers which we cannot pass.

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.

And as it is the most generous souls who have most gratitude, it is those who have most pride, and who are most base and infirm, who most allow themselves to be carried away by anger and hatred.

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

I think; therefore I am.

A state is better governed which has few laws, and those laws strictly observed.

We never understand a thing so well,and make it our own, as when we have discovered it for ourselves.