I like better for one to say some foolish thing upon important matters than to be silent. That becomes the subject of discussion and dispute, and the truth is discovered.
Denis DiderotAll things must be examined, debated, investigated without exception and without regard for anyone's feelings.
Denis DiderotThe following general definition of an animal: a system of different organic molecules that have combined with one another, under the impulsion of a sensation similar to an obtuse and muffled sense of touch given to them by the creator of matter as a whole, until each one of them has found the most suitable position for its shape and comfort.
Denis DiderotA 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.
Denis DiderotHow old the world is! I walk between two eternities.... What is my fleeting existence in comparison with that decaying rock, that valley digging its channel ever deeper, that forest that is tottering and those great masses above my head about to fall? I see the marble of tombs crumbling into dust; and yet I don't want to die!
Denis Diderot