If reason be a gift of Heaven, and we can say as much of faith, Heaven has certainly made us two gifts not only incompatible, but in direct contradiction to each other. In order to solve the difficulty, we are compelled to say either that faith is a chimera or that reason is useless.

A thing is not proved just because no one has ever questioned it. What has never been gone into impartially has never been properly gone into. Hence scepticism is the first step toward truth. It must be applied generally, because it is the touchstone.

I am more affected by the attractions of virtue than by the deformities of vice; I turn gently away from the wicked and I fly to meet the good. If there is in a literary work, in a character, in a picture, in a statue, a beautiful spot, that is where my eyes rest; I see only that, I remember only that, all the rest is well-nigh forgotten. What becomes of me when the whole work is beautiful!

You live as if you were destined to live forever, no thought of your frailty ever enters your head, of how much time has already gone by you take no heed. You squander time as if you drew from a full and abundant supply, so all the while that day which you bestow on some person or thing is perhaps your last. You have all the fears of mortals and all the desires of immortals… What foolish forgetfulness of mortality to defer wise resolutions to the fiftieth or sixtieth year, and to intend to begin life at a point to which few have attained.

Anyone who takes it upon himself, on his private authority, to break a bad law, thereby authorizes everyone else to break the good ones.

As long as the centuries continue to unfold, the number of books will grow continually, and one can predict that a time will come when it will be almost as difficult to learn anything from books as from the direct study of the whole universe. It will be almost as convenient to search for some bit of truth concealed in nature as it will be to find it hidden away in an immense multitude of bound volumes.

You risk just as much in being credulous as in being suspicious.