Miracles - C. S. Lewis [49]
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ON PROBABILITY
Probability is founded on the presumption of a resemblance between those objects of which we have had experience and those of which we have had none; and therefore it is impossible that this presumption can arise from probability.
HUME, Treatise of Human Nature, I, iii, vi.
The argument up to date shows that miracles are possible and that there is nothing antecedently ridiculous in the stories which say that God has sometimes performed them. This does not mean, of course, that we are committed to believing all stories of miracles. Most stories about miraculous events are probably false: if it comes to that, most stories about natural events are false. Lies, exaggerations, misunderstandings and hearsay make up perhaps more than half of all that is said and written in the world. We must therefore find a criterion whereby to judge any particular story of the miraculous.
In one sense, of course, our criterion is plain. Those stories are to be accepted for which the historical evidence is sufficiently good. But then, as we saw at the outset, the answer to the question, ‘How much evidence should we require for this story?’ depends on our answer to the question, ‘How far is this story intrinsically probable?’ We must therefore find a criterion of probability.
The ordinary procedure of the modern historian, even if he admits the possibility of miracle, is to admit no particular instance of it until every possibility of ‘natural’ explanation has been tried and failed. That is, he will accept the most improbable ‘natural’ explanations rather than say that a miracle occurred. Collective hallucination, hypnotism of unconsenting spectators, widespread instantaneous conspiracy in lying by persons not otherwise known to be liars and not likely to gain by the lie—all these are known to be very improbable events: so improbable that, except for the special purpose of excluding a miracle, they are never suggested. But they are preferred to the admission of a miracle.
Such a procedure is, from the purely historical point of view, sheer midsummer madness unless we start by knowing that any Miracle whatever is more improbable than the most improbable natural event. Do we know this?
We must distinguish the different kinds of improbability. Since miracles are, by definition, rarer than other events, it is obviously improbable beforehand that one will occur at any given place and time. In that sense every miracle is improbable. But that sort of improbability does not make the story that