What was descartes famous quotes need for a study guide due tomorrow

There are quite a few but most popular ones are

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

It is not enough to have a good mind; the main thing is to use it well.

Cogito ergo sum. (I think; therefore I am.)

The reading of all good books is like a conversation with the finest minds of past centuries.

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.

Each problem that I solved became a rule, which served afterwards to solve other problems.

The greatest minds are capable of the greatest vices as well as of the greatest virtues.