Democracy in America, Volume 2 by Alexis de Tocqueville

I have laid it down in a preceding chapter that men cannot do without dogmatical belief; and even that it is very much to be desired that such belief should exist amongst them. I now add, that of all the kinds of dogmatical belief the most desirable appears to me to be dogmatical belief in matters of religion; and this is a very clear inference, even from no higher consideration than the interests of this world. There is hardly any human action, however particular a character be assigned to it, which does not originate in some very general idea men have conceived of the Deity, of his relation to mankind, of the nature of their own souls, and of their duties to their fellow-creatures. Nor can anything prevent these ideas from being the common spring from which everything else emanates.

Men are therefore immeasurably interested in acquiring fixed ideas of God, of the soul, and of their common duties to their Creator and to their fellow-men; for doubt on these first principles would abandon all their actions to the impulse of chance, and would condemn them to live, to a certain extent, powerless and undisciplined.