 For Swinburne, rational acceptance of a revelatory claim must be based on evidence, and how strong the evidence needs to be depends on what background beliefs we have. If we have good reason to believe, independently of any purported revelation, that God exists and that a revelation from him is to be expected, then rational acceptance of a revelatory claim can be based on more modest evidence than would otherwise be the case. It is hence important for Swinburne to build a case for the existence of God based on natural theology, and then establish the likelihood of a revelation on the basis of a priori reasoning about what God is likely to do.