Scriptural accounts of miracles are often presented as persuasive evidence of the existence of God and his intervention in human affairs. Such accounts are common to most religions and are plentiful in the Bible: the parting of the Red Sea, the sun going backwards, speaking asses and manna from heaven in the Old Testament; walking on water, feeding the five thousand, healing lepers and resurrecting the dead in the New Testament. In addition, claims of miraculous events occur even in our own times: bleeding statues and apparitions of the Madonna are familiar examples.
The term miracle is also used in non-theological contexts: we talk of ‘the miracle of birth’, for example, and sometimes apply the term to unlikely but fortuitous events. Accordingly, the philosophical approach to miracles starts with a definition.
The very concept of a miracle implies a distinction between the natural and the supernatural. For an event to be miraculous, there needs to be a suspension or interruption of the natural course of events. David Hume defined a miracle as:
... a transgression of a law of nature by a particular volition of the Deity, or by the interposition of some invisible agent. Enquiry Concerning Human Understanding §90.fn
Clearly no natural event, however remarkable, can violate a law of nature: on the contrary, the law would have to be adjusted to allow for such an event. We must therefore understand nature as a closed system into which – in the event of a miracle – a supernatural force intervenes. Such a definition rules out those events which, however improbable or apparently meaningful, occur within natural laws.
Some philosophers have preferred to leave the laws of nature intact and define a miracle as a providential ordering of natural events. For instance, in Acts 16:25f Paul and Silas are in prison praying when an earthquake strikes and the prison doors fall open allowing them to escape. No doubt the earthquake arrived in answer to their prayers, but however fortuitous its occurrence, it is nevertheless a strictly natural event. What makes such events miraculous is their meaning: by this definition, a miracle is a revelation of God’s intentions and its significance lies in how it is interpreted. R M Hare’s description of ‘bliks’ as frameworks within which we develop our own standards of evidence, is intended to show that religious concepts are particular interpretations of the world, not objective facts: since a miracle is its meaning, then with the right blik, anything revelatory can appear miraculous. In a similar vein, Wittgenstein understood miracles as ‘gestures’ and located their meaning in the context of the religious ‘form of life’:
As a man sits quietly and then makes an impressive gesture, God lets the world run on smoothly and then accompanies the words of a saint by a symbolic occurrence, a gesture of nature. Culture and Value
This allows for seemingly natural events to count as miracles and places emphasis instead upon how they acquire significance in context. But such a definition leads to a problem. If miracles are to count as evidence for God’s existence, then they must not be susceptible to other explanations: otherwise it seems impossible to determine which events are to count as miracles and which are not. If it is merely a question of how we interpret them, then this determination becomes an entirely subjective matter. Certainly the meaning of a miraculous event as a revelation of God is important, but on its own it is not enough to define a miracle – or convince a sceptic.
And this is the central issue. Since we cannot by definition account for miracles by adopting the scientific viewpoint, the philosophical question is to what extent miracles can or should be considered reliable evidence for the existence of God. The classic examination of this question was given by David Hume in Section X of his Enquiry Concerning Human Understanding.
Hume’s analysis of miracles is epistemological in form: that is, he is interested first and foremost in how we should respond to accounts of miraculous events. His primary target is the reliability of those witnesses who claim to have observed miracles first-hand, and his conclusion is unequivocal:
... no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact which it endeavours to establish. Enquiry §91
In other words, when faced with an account of a miracle occurring, we have to ask which is more likely: the miracle being real, or the account being false. There are two reasons why an account of a miracle might be false: the witness is either mistaken or lying. Of course, error and deception both come in many forms and not every testimony of a miracle is likely to be an act of deliberate duplicity, but such details are not relevant to Hume’s argument. The point is that if we are asked to believe that a miracle has occurred, it is reasonable to wonder whether a more mundane explanation is actually more likely. On the surface, it appears that Hume is allowing the possibility that such testimony could, in exceptional circumstances, be more plausible than the likelihood of error, and therefore be reasonable evidence for the occurrence of a miracle. But this seems impossible if we define a miracle as a transgression or violation of natural laws (which appears necessary if they are to have religious significance). Hume is effectively saying that by definition no miracle will ever be more plausible than the probability of witness error. The argument leaves open the possibility of an extraordinary event occurring, as long as that event is not contrary to natural laws: such bizarre or freak events do happen, of course, and therefore we can reasonably trust witnesses to these events as long as they meet normal standards of reliability.
In the case of miracles, these standards are never met. Hume gives five further reasons as to why this is the case. First, there has always been a lack of reputable, independent witnesses to any miraculous event. Second, people are naturally credulous and take delight in the surprise and wonder that unusual events excite. This is no doubt true: history is full of people being taken in by hoaxes or willingly accepting outrageous claims. The recent phenomena of alien abduction claims, crop circles and alleged global conspiracies attest to this continuing propensity. Third, miraculous events have generally occurred among uneducated or primitive peoples who lack alternative explanations for what they have seen. Modern understanding of medicine can explain prophetic voices as schizophrenia, miraculous cures as psychosomatic relief, and so on – but accounts of miracles become received wisdom before any tradition of rational enquiry develops. Fourth, each miracle claimed in support of one religion in fact denies the truth of another: the competing claims of different religions therefore cancel each other out. Fifth and finally, since stories of miracles usually appear in the early years of a new faith, or at least are adduced to support an existing one, then there is much to be gained by being a witness to such an event. Indeed, most religions frown upon doubt or caution and encourage credulity in their followers – and who would not wish to be present at a supernatural event?
These five arguments are admittedly of variable quality, but taken together they do erode our trust in any claim to have witnessed a miracle: and the less trustworthy such a claim is, the more reasonable it is to discount it. Hume’s point therefore remains that the balance of probabilities will always be against the miraculous. There is, on the other hand, nothing miraculous about false testimony.
One objection to Hume’s analysis is that his standard of reasonable evidence is too high. After all, we take many things ‘on faith’ and they usually turn out to be true: we recognise as authoritative many people whose claims we believe without a problem. We also accept much first-hand testimony as reliable, especially when independent witnesses corroborate a claim. However, the key notions here are those of authority and independence. In the case of miracles, the witnesses are rarely people of trusted authority, and apparently independent testimony usually turns out, on investigation, to derive from a shared tradition. In the case of miracles a great deal is at stake; and given the nature of miracles as maximally improbable, it is hard to envision any testimony that would be trustworthy enough to override this.
A final point to be made is that the same argument holds true for any individual fortunate enough to witness a miracle. The sheer unlikelihood of the event being definitively miraculous will make other explanations more likely: we are often mistaken about what we see or interpret evidence wrongly, and it is only reasonable to doubt our own eyes and prefer error as an explanation over any violation of the laws of nature.
Of course, for the theist there is nothing improbable about God’s intervention in the natural world: if an omnipotent and loving God does exist, it seems likely that he will make himself known from time to time. Miracles do not, therefore, represent a logical problem. However, the question remains to what extent claims of miracles can reasonably count as evidence for the existence of God. For the sceptic, they appear to have no evidential value at all. As Hume remarked with deliberate irony:
... whoever is moved by Faith to assent to [Christianity], is conscious of a continued miracle in his own person, which subverts all the principles of his understanding. Enquiry §101