Atheists, secular humanists, agnostics, and deists commonly affirm that belief should be proportioned to the evidence, that the strength of one's conviction ought to match the strength of the reasons and evidence supporting it, and that claims lacking sufficient support should be doubted or withheld rather than accepted on faith or authority. The four positions apply the principle differently. Atheism itself divides between what philosophers sometimes call a strong or positive form, the affirmative claim that no god exists, and a weaker or negative form, sometimes argued for by philosophers such as Antony Flew under the label a presumption of atheism, which withholds belief in any god for lack of sufficient evidence without claiming to have positively disproved the possibility, a distinction close to, though not identical with, the line agnosticism draws between atheism and theism as a matter of knowledge rather than belief.
Deism represents a historically distinct application of the same evidentialist instinct: rather than concluding that no god exists, Enlightenment deists such as Voltaire and, in his later writings, Thomas Paine in The Age of Reason, argued that reason and the observable order of nature support belief in a creator God who set the universe in motion, while rejecting miracles, revelation, and organized religious authority as unsupported by the same evidential standard, a position that lets deism affirm a Creator while still applying the evidentialist principle strictly against claims of specific scriptural revelation.