| Each problem that I solved became a rule, which served afterwards to solve other problems. |
| It is not enough to have a good mind the main thing is to use it well. |
| The greatest minds are capable of the greatest vices as well as of the greatest virtues. |
| Good sense is of all things in the world the most equally distributed, for everybody thinks he is so well supplied with it, that even those most difficult to please in all other matters never desire more of it than they already possess. |
| Nothing is more fairly distributed than common sense - no one needs more of it than one already has |
| Cogito, ergo, sum. (I think therefore I am.) |
| Your joy is your sorrow unmasked. And the self-same well from which your laughter rises was often-times filled with your tears. |
| The reading of all good books is indeed like a conversation with the noblest men of past centuries who were the authors of them, nay a carefully studied conversation, in which they reveal to us none but the best of their thoughts. |
| Cogito ergo sum. |
| It is only prudent never to place complete confidence in that by which we have even once been deceived. |
| In order to improve the mind, we ought less to learn, than to contemplate. |
| One cannot conceive anything so strange and so implausible that it has not already been said by one philosopher or another. |
| The first precept was never to accept a thing as true until I knew it as such without a single doubt. |
| 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. |
