According to Hume rational belief is proportioning ‘our belief to the available evidence’ (p. 83). This is obviously a controversial claim!
For Hume, complete agreement in evidence is a ‘proof’. If in our experience every time metal is heated it expands, and every one else agrees, then this is a ‘proof’ and it justifies calling it ‘a law of nature’. If an event happens a certain proportion of the time then Hume calls it a ‘probability’. As Dowe points out, ‘establishing the truth of a law of nature is not as straightforward as Hume apparently imagines’ (p. 85).
Testimonial evidence is evidence obtained from the statements of others; this may come from a number of different sources: for example, from someone’s CV; from witnesses in a court of law; or from findings published in a scientific journal.
Hume argues that evaluating testimony involves: (i) how probable the event itself is; and (ii) the reliability of the witness. To this we might add (iii) the number of independent witnesses.
How we define a miracle is important. Is it a ‘very unlikely event’ or ‘an impossible event’, then obviously if we accept the former there will be many more miracles than if we accept the latter! Hume defines it as a ‘violation of the laws of nature’; a violation of uniform regularities. The question remains, is this a coherent concept of a miracle? If one metal when heated does not expand, then we question the law of nature, it is not a universal regularity, rather than claiming that it is a miracle.
Hume in his first argument against miracles argues that we cannot rationally believe that a miracle has occurred. If such evidence that amounted to a proof did exist that a violation of a law of nature had occurred, then we would have two full proofs, one for the miracle and one for the law of nature it is supposed to transgress. What are we then to do? Hume’s theory is that these two proofs will balance each other out and we should remain agnostic about the miracle occurring.
Hume’s second argument is that even if miracles did occur it wouldn’t necessarily be evidence for any religious claim. It may be that there is no explanation for it or that there will be some natural explanation that has not yet been found. Thus for Hume the burden of proof is upon the theist, she must prove that a miracle has occurred and that it is from God and has no natural explanation.
Dowe then turns to George Schlesinger’s defence of miracles. Schelsinger in his Religion and the Scientific Method (1977) uses the principle to best explanation, an argument often used in science, to defend the rationality of miracles: Schlesinger applies the methodology of science to religion.
Dowe concludes that if religion can use the methods of science then there is a common rationality shared by ‘science and religion’.