"A philosopher-people would be a people of searchers, and a people, under pain of death, must know and not search."--Louis de Bonald, Recherches Philosophiques
The usual arguments for free speech assume that the state always needs to be testing its official beliefs. In some ways, this is rather dumb. Individual people must firmly believe that many things are true, if they are to live; societies must also firmly believe that many things are true, if they are to live.
A man who believes nothing can do nothing, for all action is for the sake of what you believe to be good. Thus, modern man is characteristically vacillating and spontaneous in his action; swift to follow what appears good, and equally swift in abandoning its pursuit. He is free only to be inconstant, because his freedom consists in being unmoored from any fixed position. And so he is a man who seems to be nothing inside, because he has never dedicated himself to anything outside himself.
A society that believes nothing, similarly, can also do nothing. The United States is also vacillating in its policies, switching them from year to year with the emotional whims of the voters, the power of the lobbyists, and the events of the moment. Because it believes nothing, it will only wander aimlessly until, as do all things that follow nothing, it descends to nothing.