Scepticism is the first step towards truth.

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.

This root [the potato], no matter how much you prepare it, is tasteless and floury. It cannot pass for an agreeable food, but it supplies a food sufficiently abundant and sufficiently healthy for men who ask only to sustain themselves. The potato is criticized with reason for being windy, but what matters windiness for the vigorous organisms of peasants and laborers?

In order to get as much fame as one's father one has to much more able than he.

The man who first pronounced the barbarous word God ought to have been immediately destroyed.

Isn't it better to have men being ungrateful than to miss a chance to do good?

Which is the greater merit, to enlighten the human race, which remains forever, or to save one's fatherland, which is perishable?