My third maxim was to endeavour always to conquer myself rather than fortune, and change my desires rather than the order of the world, and in genera… - René Descartes

Except our own thoughts, there is nothing absolutely in our power.

Reading good books is like engaging in conversation with the most cultivated minds of past centuries who had composed them, or rather, taking part in a well-conducted dialogue in which such minds reveal to us only the best of their thoughts.

was most keen on mathematics, because of its certainty and the incontrovertibility* of its proofs; but I did not yet see its true use. Believing as I did that its only application was to the mechanical arts,* I was astonished that nothing more exalted had been built on such sure and solid foundations; whereas, on the other hand, I compared the moral works of ancient pagan writers to splendid and magnificent palaces built on nothing more than sand and mud.

I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.