Richard Swinburne has appealed to what he calls the “principle of credulity” in support of the argument from religious experience.

The Principle of Credulity

The principle of credulity states that if it seems to a subject that x is present, then probably x is present. Generally, says Swinburne, it is reasonable to believe that the world is probably as we experience it to be. Unless we have some specific reason to question a religious experience, therefore, then we ought to accept that it is at least prima facie evidence for the existence of God.

Experiences of the Absence of God

Atheist Michael Martin has criticised Swinburne’s use of the principle of credulity. If, as Swinburne suggests, experiences are generally to be treated as veridical, i.e. as accurately representing the world, then this allows an argument from the absence of religious experience to be constructed. An atheist who experiences the absence of God can argue, using the principle of credulity, that the world is probably as this experience represents it as being: godless. Arguments from religious experiences to the existence of God can thus be met with arguments from atheist experiences to the non-existence of God; what will result will, presumably, be a tie, other things being equal.

Against the Negative Principle of Credulity

Swinburne responds to this objection by arguing that this negative principle of credulity is false. Swinburne carefully states his positive principle of credulity—if it seems to a subject that x is present, then probably x is present—so that it does not apply to experiences of absences. The negative principle—if it seems to a subject that x is not present, then probably x is not present—he rejects.

This negative principle, he suggests, would only be a good one in cases where it is reasonable to believe that if x were present then the subject would experience x. There is no reason, however, to suppose that if God existed then the atheist would experience him, and so the negative principle of credulity does not apply to atheists‘ experiences of the absence of God.