Skepticism and Miracles

What is a miracle? In the vernacular we speak of "miraculous" escapes and the like, to characterise events which are extremely unlikely - at odds with the normal course of experience. A miracle in this weak sense just means a very improbable event.

David Hume, in his famous essay "On Miracles", had a stronger sense of "miracle" in mind, namely something which violates a law of nature. It is in this sense that miracles have commonly featured in religious systems of belief, as the means by which God has been thought to have demonstrated His presence or His power to His chosen people.

The question which Hume addresses is: are we justified in believing that miracles have in fact occurred? He argues for the very strong conclusion that we are never justified in believing that a miracle has ever occurred.

Hume is not claiming to show that miracles have never occurred. Proving negative existence claims is notoriously problematic. Hume's claim is the importantly different one that we are never rationally justified in believing that miracles have occurred. That is, Hume is addressing the epistemological issue of what it is rational to believe, rather than the metaphysical question of what is and is not possible in our sort of world.

… In evaluating testimony for miracles, Hume advances the following principle which, echoing the famous methodological principle commonly attributed to William of Ockham (c. 1285-1349), has been called Hume's Razor. The principle is:

No testimony is sufficient to establish a miracle unless that testimony be of such a kind that its falsehood would be more miraculous than the fact which it endeavours to establish.

- From NZ Skeptic 28, June 1993.