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. - Denis Diderot
She believed in nothing. Only her scepticism kept her from being an atheist. - Jean-Paul Sartre
Latter-day scepticism is fond of calling itself progressive; but scepticism is really reactionary. Scepticism goes back; it attempts to unsettle what has already been settled. Instead of trying to break up new fields with its plough, it simply tries to break up the plough. - G.K. Chesterton