The present is great with the future.

Imaginary numbers are a fine and wonderful refuge of the divine spirit almost an amphibian between being and non-being.

Men act like brutes in so far as the sequences of their perceptions arise through the principle of memory only, like those empirical physicians who have mere practice without theory.

Our reasonings are grounded upon two great principles, that of contradiction, in virtue of which we judge false that which involves a contradiction, and true that which is opposed or contradictory to the false.

It has long seemed ridiculous to me to suppose that the nature of things has been so poor and stingy that it provided souls only to such a trifling mass of bodies on our globe, like human bodies, when it could have given them to all, without interfering with its other ends.

It is a good thing to proceed in order and to establish propositions. This is the way to gain ground and to progress with certainty.

There is nothing without reason.