Richard Swinburne

The author argues that a historical hypothesis h is probable in so far as it is intrinsically a simple hypothesis and (1) the posterior historical evidence is such as probably would occur if h is true, but not otherwise, (2) the general background evidence makes it probable that h is to be expected under certain conditions, and not otherwise, (3) there is evidence, the prior historical evidence’ such as probably would occur if these conditions were satisfied, but not otherwise. By the ‘posterior historical evidence’ is meant the testimony of witnesses and physical traces caused by what happened at the time in question. In the case of the resurrection of Jesus the general background evidence which makes it probable that there is a God of the traditional kind who has good reason to become incarnate in order to provide atonement, to identify with us in our suffering, and to reveal teaching. The prior historical evidence that there was prophet who led the kind of life that incarnate God would need to lead if he had become incarnate for these reason. He will need to show us when some prophet has led the right sort of life that God has lived it, and that can be achieved by his life being culminated by a super-miracle such as the resurrection. The posterior historical evidence is the evidence of witnesses to the empty tomb and the appearances of Jesus. The stronger is the general background evidence, and the stronger is the prior historical evidence showing that one and only one prophet (Jesus) led the right sort of life, the less our need of posterior historical evidence. Given some modest values for (1), (2), (3), there is a very high probability that the resurrection occurred. This is illustrated by feeding some artificially precise values for these probabilities into the relevant theorem of the probability calculus, Bayes’ Theorem.

Arguments move from premises to conclusions. The premises state things taken temporally for granted; if the argument works, the premises provide grounds for affirming the conclusion. A valid deductive argument is one in which the premises necessitate, that is, entail, the conclusion. What I shall call a ‘correct’ inductive argument is one in which the premises in some degree probabilify the conclusion, but do not necessitate it. More precisely, in what I shall call a correct P-inductive argument the premises make the conclusion probable ; in what I shall call a correct C-inductive argument, the premises add to the probability of the conclusion. Arguments only show their conclusions to be true if they start from true premises; arguments of the above types which work and do start from such premises I will call sound arguments. Arguments are only of use to show to an individual that the conclusion is true if he already knows the premises to be true. Most of what I shall have to say today concerns arguments with respect to which there is no doubt that the premises are true.

On what grounds will the rational man become a Christian? It is often assumed by many, especially non-Christians, that he will become a Christian if and only if he judges that the evidence available to him shows that it is more likely than not that the Christian theological system is true, that, in mathematical terms, on the evidence available to him, the probability of its truth is greater than half. It is the purpose of this paper to investigate whether or not this is a necessary and sufficient condition for the rational man to adopt Christianity