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

Archimedes, that he might transport the entire globe ... demanded only a point that was firm and immovable; so also, I shall be entitled to entertain the highest expectations, if I am fortunate enough to discover only one thing that is certain and indubitable.

Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something.

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

He lives well who is well hidden.

If we possessed a thorough knowledge of all the parts of the seed of any animal (e.g. man), we could from that alone, be reasons entirely mathematical and certain, deduce the whole conformation and figure of each of its members, and, conversely if we knew several peculiarities of this conformation, we would from those deduce the nature of its seed.

The principal effect of the passions is that they incite and persuade the mind to will the events for which they prepared the body.