The best illustration of the power and impact of America’s original philosophical radicalism may be discovered in the first sentence of the nation’s first founding document. Many historians today take for granted that the reference in the preamble of the Declaration of Independence to “the laws of Nature and of Nature’s God” amounts to a gesture of conventional piety — and no doubt it was written partly in order to be read in this way. Religious conservatives today routinely celebrate it as proof that America is founded as a Christian nation. These and similar interpretations serve mainly to express some deep and persistent assumptions about the nature of human experience: that we govern ourselves through acts of faith; that all authority must rest on the assertion of belief in some higher authority; and that all would be well if we could return to the simple faith of our fathers.
Yet, “Nature’s God” properly belongs to the radical philosophical religion of deism. It refers to nothing that we commonly mean by the term “God,” but rather to something closer to “Nature.” It tells us that we are and always have been the source of our own authority; that we govern ourselves not through acts of faith but through acts of understanding; and that if we should find ourselves beholden to some other imagined authority, this can only mean that we have constructed the conditions of our own servitude. The Declaration of Independence — precisely where it superficially seems to invoke the blessing of the established religion — really stands for an emancipation of the political order from God.
— pp. 6-7, Matthew Stewart, Nature’s God: The Heretical Origins of the American Republic