Wandering in a vast forest at night, I have only a faint light to guide me. A stranger appears and says to me: 'My friend, you should blow out your candle in order to find your way more clearly.' This stranger is a theologian.

No man has received from nature the right to give orders to others. Freedom is a gift from heaven, and every individual of the same species has the right to enjoy it as soon as he is in enjoyment of his reason.

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.

I picture the vast realm of the sciences as an immense landscape scattered with patches of dark and light. The goal towards which we must work is either to extend the boundaries of the patches of light, or to increase their number. One of these tasks falls to the creative genius; the other requires a sort of sagacity combined with perfectionism.

Scepticism is the first step towards truth.

Scepticism is the first step toward truth.

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.