In order to seek truth, it is necessary once in the course of our life, to doubt, as far as possible, of all things. - René Descartes

"Instead of René Descartes' famous "Cogito ergo sum" (I think, therefore I am), I propose "Communico ergo sum," (I communicate, therefore I exist") as the philosophical proof of man's existence.

On the other hand, I compared the disquisitions of the ancient moralists to very towering and magnificent palaces with no better foundation than sand and mud:

Il est bon de savoir quelque chose des moeurs de divers peuples, afin de juger des nôtres plus sainement, et que nous ne pensions pas que tout ce qui est contre nos modes soit ridicule et contre raison, ainsi qu'ont coutume de faire ceux qui n'ont rien vu.