This is a shared epistemic commitment across the skeptical and rationalist worldviews, underlying the atheist's conclusion that gods do not exist or should not be believed in, the agnostic's suspension of judgment, the deist's preference for reason over revelation, and the humanist's reliance on science and free inquiry as the proper guide to belief and conduct. It descends from the Enlightenment and the rise of the modern scientific method, and expresses a conviction that intellectual honesty requires following the evidence where it leads rather than assuming a conclusion in advance.
The principle has not gone unchallenged, including from within philosophy rather than only from religious believers. The philosopher William James, responding directly to the strict evidentialism associated with W. K. Clifford, argued in his essay The Will to Believe that certain kinds of questions, live options that are forced and momentous rather than trivial or avoidable, cannot always wait on sufficient evidence before a person must, in practice, decide how to live, and that in such cases a passional or volitional element in belief is unavoidable and not necessarily irrational. Defenders of strict evidentialism have generally responded that James's argument, whatever its merits for practical choices, does not license treating factual claims about what exists as though they could be settled by preference, keeping the underlying dispute over evidentialism's proper scope very much alive.