This is the essential argument of Hume's famous disquisition upon miracles; and it may safely be declared to be irrefragable. But it must be admitted that Hume has surrounded the kernel of his essay with a shell of very doubtful value.
The first step in this, as in all other discussions, is to come to a clear understanding as to the meaning of the terms employed. Argumentation whether miracles are possible, and, if possible, credible, is mere beating the air until the arguers have agreed what they mean by the word "miracles."
Hume, with less than his usual perspicuity, but in accordance with a common practice of believers in the miraculous, defines a miracle as a "violation of the laws of nature," or as "a transgression of a law of nature by a particular volition of the Deity, or by the interposition of some invisible agent."
"be an uniform experience against every miraculous event, otherwise the event would not merit that appellation. And as an uniform experience amounts to a proof, there is here a direct and full proof, from the nature of the fact, against the existence of any miracle; nor can such a proof be destroyed or the miracle rendered credible but by an opposite proof which is superior."--(IV. p. 134.)
Every one of these dicta appears to be open to serious objection.
The word "miracle"--_miraculum_,--in its primitive and legitimate sense, simply means something wonderful.
Cicero applies it as readily to the fancies of philosophers, "Portenta et miracula philosophorum somniantium," as we do to the prodigies of priests. And the source of the wonder which a miracle excites is the belief, on the part of those who witness it, that it transcends or contradicts ordinary experience.
The definition of a miracle as a "violation of the laws of nature" is, in reality, an employment of language which, on the face of the matter, cannot be justified. For "nature" means neither more nor less than that which is; the sum of phenomena presented to our experience; the totality of events past, present, and to come. Every event must be taken to be a part of nature, until proof to the contrary is supplied. And such proof is, from the nature of the case, impossible.
"Why is it more than probable that all men must die: that lead cannot of itself remain suspended in the air: that fire consumes wood and is extinguished by water; unless it be that these events are found agreeable to the laws of nature, and there is required a violation of those laws, or in other words, a miracle, to prevent them?"--(IV. p. 133.)