Although my knowledge grows more and more, nevertheless I do not for that reason believe that it can ever be actually infinite, since it can never reach a point so high that it will be unable to attain any greater increase.

I accept no principles of physics which are not also accepted in mathematics.

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 God there is an infinitude of things which I cannot comprehend, nor possibly even reach in any way by thought; for it is the nature of the infinite that my nature, which is finite and limited, should not comprehend it.

Divide each difficulty into as many parts as is feasible and necessary to resolve it.

If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.

Truths are more likely to be discovered by one man than by a nation