appears, is the doctrine which, on the occasion of an attempt to apply it to the question of the credibility of miracles, excited so violent a controversy. Hume's celebrated doctrine, that nothing is credible which is contradictory to experience or at variance with laws of nature, is merely this very plain and harmless proposition, that whatever is contradictory to a complete induction is incredible."(1) He then proceeds to meet possible objections: "But does not (it may be asked) the very statement of the proposition imply a contradiction? An alleged fact according to this theory is not to be believed if it contradict a complete induction. But it is essential to the completeness of an induction that it should not contradict any known fact. Is it not, then, a petitio principii to say, that the fact ought to be disbelieved because the induction to it is complete? How can we have a right to declare the induction complete, while facts, supported by credible evidence, present themselves in opposition to it? I answer, we have that right whenever the scientific canons of induction give it to us; that is, whenever the induction can be complete. We have it, for example, in a case of causation in which there has been an experimentum cruris." It will be remarked that Dr. Farrar adopts Mr. Mill's phraseology in one of the above questions to affirm the reverse of his opinion. Mr. Mill decides that the proposition is not a petitio principii; Dr. Farrar says, as in continuation of his reference to Mr. Mill, that it is a flagrant petitio principii. Mr. Mill proceeds to prove his statement, and he naturally argues that, if observations or experiments have been repeated so often, and by so many persons, as to exclude all supposition of
error in the observer, a law of nature is established; and so long as this law is received as such, the assertion that on any particular occasion the cause A took place and yet the effect B did not follow, without any counteracting cause, must be disbelieved. In fact, as he winds up this part of the argument by saying: "We cannot admit a proposition as a law of nature, and yet believe a fact in real contradiction to it. We must disbelieve the alleged fact, or believe that we were mistaken in admitting the supposed law."(1) Mr. Mill points out, however, that, in order that any alleged fact should be contradictory to a law of causation, the allegation must be not simply that the cause existed without being followed by the effect, but that this happened in the absence of any adequate counteracting cause. "Now, in the case of an alleged miracle, the assertion is the exact opposite of this. It is, that the effect was defeated, not in the absence, but in consequence of a counteracting cause, namely, a direct interposition of an act of the will of some being who has power over nature; and in particular of a Being, whose will being assumed to have endowed all the causes with the powers by which they produce their effects, may well be supposed able to counteract them."(2) A miracle, then, is no contradiction to the law of cause and effect; it is merely a new effect supposed to be introduced by the introduction of a new cause; "of the adequacy of that cause if present,(3) there can be no doubt; and the only antecedent improbability which can be ascribed to the miracle is the improbability that any such cause existed." Mr. Mill then continues, resuming his criticism on Hume's argument:
"All, therefore, which Hume has made out, and this he must be considered to have made out, is that (at least in the imperfect state of our knowledge of natural agencies, which leaves it always possible that some of the physical antecedents may have been hidden from us,) no evidence can prove a miracle to any one who did not previously believe the existence of a being or beings with supernatural power; or who believes himself to have full proof that the character of the Being whom he recognizes is inconsistent with his having seen fit to interfere on the occasion in question." Mr. Mill proceeds to enlarge on this conclusion. "If we do not already believe in supernatural agencies, no miracle can prove to us their existence. The miracle itself, considered merely as an extraordinary fact, may be satisfactorily certified by our senses or by testimony; but nothing can ever prove that it is a miracle: there is still another possible hypothesis, that of its being the result of some unknown natural cause: and this possibility cannot be so completely shut out as to leave no alternative but that of admitting the existence and intervention of a being superior to nature. Those, however, who already believe in such a being have two hypotheses to choose from, a supernatural, and an unknown natural agency; and they have to judge which of the two is the most probable in the particular case. In forming this judgment, an important element of the question will be the conformity of the result to the laws of the supposed agent; that is, to the character of the Deity as they conceive it. But, with the knowledge which we now possess of the general uniformity of the course of nature, religion, following in the wake of science, has been compelled to acknowledge the government of the universe as
being on the whole carried on by general laws, and not by special interpositions. To whoever holds this belief, there is a general presumption against any supposition of divine agency not operating through general laws, or, in other words, there is an antecedent improbability in every miracle, which, in order to outweigh it, requires an extraordinary strength of antecedent probability derived from the special circumstances of the case."(1) Mr. Mill rightly considers that it is not more difficult to estimate this than in the case of other probabilities. "We are seldom, therefore, without the means (when the circumstances of the case are at all known to us) of judging how far it is likely that such a cause should have existed at that time and place without manifesting its presence by some other marks, and (in the case of an unknown cause) without having hitherto manifested its existence in any other instance. According as this circumstance, or the falsity of the testimony, appears more improbable, that is, conflicts with an approximate generalization of a higher order, we believe the testimony, or disbelieve it; with a stronger or weaker degree of conviction, according to the preponderance: at least until we have sifted the matter further."(2) This is precisely Hume's argument weakened by the introduction of reservations which have no cogency.
"We have wished to avoid interrupting Mr. Mill's train of reasoning by any remarks of our own, and have, therefore, deferred till now the following observations regarding his criticism on Hume's argument.
In reducing Hume's celebrated doctrine to the very plain proposition that whatever is contradictory to a complete induction is incredible, Mr. Mill in no way
