René Descartes, Discourse On Method Quotes
It is not enough to have a good mind. The main thing is to use it well.
Each problem that I solved became a rule, which served afterwards to solve other problems.
And thus, the actions of life often not allowing any delay, it is a truth very certain that, when it is not in our power to determine the most true opinions we ought to follow the most probable.
The dreams we imagine when we are asleep should not in any way make us doubt the truth of the thoughts we have when we are awake.