Hume / (English Men of Letters Series)

by Thomas Henry Huxley

Moreover, not to repeat what has been said respecting the absurdity of supposing that something which occurs is a transgression of laws, our only knowledge of which is derived from the observation of that which occurs; upon what sort of evidence can we be justified in concluding that a given event is the effect of a particular volition of the Deity, or of the interposition of some invisible (that is unperceivable) agent? It may be so, but how is the assertion, that it is so, to be tested? If it be said that the event exceeds the power of natural causes, what can justify such a saying? The day-fly has better grounds for calling a thunderstorm supernatural, than has man, with his experience of an infinitesimal fraction of duration, to say that the most astonishing event that can be imagined is beyond the scope of natural causes.

"Whatever is intelligible and can be distinctly conceived, implies no contradiction, and can never be proved false by any demonstration, argument, or abstract reasoning a priori."—(IV. p. 44.)

So wrote Hume, with perfect justice, in his Sceptical Doubts. But a miracle, in the sense of a sudden and complete change in the customary order of nature, is intelligible, can be distinctly conceived, implies no contradiction; and, therefore, according to Hume's own showing, cannot be proved false by any demonstrative argument.

Nevertheless, in diametrical contradiction to his own principles, Hume says elsewhere:—

"It is a miracle that a dead man should come to life: because that has never been observed in any age or country."—(IV. p. 134.)

That is to say, there is an uniform experience against such an event, and therefore, if it occurs, it is a violation of the laws of nature. Or, to put the argument in its naked absurdity, that which never has happened never can happen, without a violation of the laws of nature. In truth, if a dead man did come to life, the fact would be evidence, not that any law of nature had been violated, but that those laws, even when they express the results of a very long and uniform experience, are necessarily based on incomplete knowledge, and are to be held only as grounds of more or less justifiable expectation.

To sum up, the definition of a miracle as a suspension or a contravention of the order of Nature is self-contradictory, because all we know of the order of nature is derived from our observation of the course of events of which the so-called miracle is a part. On the other hand, no event is too extraordinary to be impossible; and, therefore, if by the term miracles we mean only "extremely wonderful events," there can be no just ground for denying the possibility of their occurrence.

But when we turn from the question of the possibility of miracles, however they may be defined, in the abstract, to that respecting the grounds upon which we are justified in believing any particular miracle, Hume's arguments have a very different value, for they resolve themselves into a simple statement of the dictates of common sense—which may be expressed in this canon: the more a statement of fact conflicts with previous experience, the more complete must be the evidence which is to justify us in believing it. It is upon this principle that every one carries on the business of common life. If a man tells me he saw a piebald horse in Piccadilly, I believe him without hesitation. The thing itself is likely enough, and there is no imaginable motive for his deceiving me. But if the same person tells me he observed a zebra there, I might hesitate a little about accepting his testimony, unless I were well satisfied, not only as to his previous acquaintance with zebras, but as to his powers and opportunities of observation in the present case. If, however, my informant assured me that he beheld a centaur trotting down that famous thoroughfare, I should emphatically decline to credit his statement; and this even if he were the most saintly of men and ready to suffer martyrdom in support of his belief. In such a case, I could, of course, entertain no doubt of the good faith of the witness; it would be only his competency, which unfortunately has very little to do with good faith or intensity of conviction, which I should presume to call in question.

Indeed, I hardly know what testimony would satisfy me of the existence of a live centaur. To put an extreme case, suppose the late Johannes Müller, of Berlin, the greatest anatomist and physiologist among my contemporaries, had barely affirmed he had seen a live centaur, I should certainly have been staggered by the weight of an assertion coming from such an authority. But I could have got no further than a suspension of judgment. For, on the whole, it would have been more probable that even he had fallen into some error of interpretation of the facts which came under his observation, than that such an animal as a centaur really existed. And nothing short of a careful monograph, by a highly competent investigator, accompanied by figures and measurements of all the most important parts of a centaur, put forth under circumstances which could leave no doubt that falsification or misinterpretation would meet with immediate exposure, could possibly enable a man of science to feel that he acted conscientiously, in expressing his belief in the existence of a centaur on the evidence of testimony.

This hesitation about admitting the existence of such an animal as a centaur, be it observed, does not deserve reproach, as scepticism, but moderate praise, as mere scientific good faith. It need not imply, and it does not, so far as I am concerned, any a priori hypothesis that a centaur is an impossible animal; or, that his existence, if he did exist, would violate the laws of nature. Indubitably, the organisation of a centaur presents a variety of practical difficulties to an anatomist and physiologist; and a good many of those generalisations of our present experience, which we are pleased to call laws of nature, would be upset by the appearance of such an animal, so that we should have to frame new laws to cover our extended experience. Every wise man will admit that the possibilities of nature are infinite, and include centaurs; but he will not the less feel it his duty to hold fast, for the present, by the dictum of Lucretius, "Nam certe ex vivo Centauri non fit imago," and to cast the entire burthen of proof, that centaurs exist, on the shoulders of those who ask him to believe the statement.