Christopher C. French
Doubt is not a pleasant mental state, but certainty is a ridiculous one.
According to Chambers English Dictionary (1988), the word 'scepticism' (or 'skepticism' to use the American spelling) is derived from the Greek words skeptikos, which means 'thoughtful', and skeptesthai, meaning 'to consider'. It is defined as 'that condition in which the mind is before it has arrived at conclusive opinions: doubt […]'. This chapter will discuss the idea of scepticism as it applies to a consideration of paranormal claims. We will begin by considering the philosophical antecedents of modern scepticism (for more detail, see Kurtz 1992).
Hume's essay Of Miracles, published in 1748, is particularly relevant to a discussion of scepticism as it relates to the paranormal (Grey 1994). Hume presented a strong argument that one would never be rationally justified in believing that a miracle had occurred. He defined a miracle as an event which violates a law of nature, a definition which would be taken by many as including paranormal events. It is important to realise that Hume was not claiming to have proved that miracles have never occurred, only that we would never be justified in believing that they have. He proposed the following principle:
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.
(Hume pp. 115-16, in Grey 1994, p. 294)
Although this principle allows for the possibility that the evidence in favour of a miracle might outweigh the evidence against it, in practice, Hume argued, this never happens. A number of factors undermine the credibility of miraculous claims, not least of which is the problem of witness reliability. Is it more likely that the person or persons making the claim are deceivers