The art of opposition and of revolution is to unsettle established customs, sounding them even to their source, to point out their want of authority … - Blaise Pascal

One must know when it is right to doubt, to affirm, to submit. Anyone who does otherwise does not understand the force of reason. Some men run counter to these three principles, either affirming that everything can be proved, because they know nothing about proof, or doubting everything, because they do not know when to submit, or always submitting, because they do not know when judgment is called for.

Those honor nature well, who teach that she can speak on everything.

I can certainly imagine a man without hands, feet, or head, for it is only experience that teaches us that the head is more necessary than the feet. But I cannot imagine a man without thought; he would be a stone or an animal.