[In an effort to promote the habit of understanding a position before accepting or rejecting it, here is my attempt at providing a close outline of the relevant passage from Hume's writings in which he argues against the rationality of testimony-based belief in miracles: Section X of his An Enquiry Concerning Human Understanding]
Section X, Part I:
0. Introductory stuff:
0.1 Quick summary of theologian John Tilotson's argument against Transubstantiation.
0.1.1 Scripture and tradition are based on the testimony of the apostles
0.1.2 But the evidence of testimony is always weaker than the evidence of the senses
0.1.3 So, even if scripture and/or tradition tell us that the bread and wine turn into the body and blood of Christ, the evidence of the senses tells us that they remain bread and wine: they have all the sensible properties of bread and wine; nothing more.
0.1.4 Therefore, since the evidence of the senses trumps the evidence of testimony, it is unreasonable to believe in Transubstantiation.
0.2 Hume claims that he has found an argument of similar force and nature, but against the rationality of belief in miracles in general: "I flatter myself, that I have found an argument of a like nature, which, if just, will, with the wise and learned, be an everlasting check to all kinds of superstitious delusion, and consequently, will be useful as long as the world endures. For so long, I presume, will the accounts of miracles and prodigies be found in all history, sacred and profane." (p. 73)
1. Setup: key notions and principles stated and explained:
1.1 On the nature of experiential evidence in general
1.1.1 Experiential evidence, which concerns matters of fact, is not infallible, but can lead to errors.
1.2 There exists the whole spectrum of frequency of conjunction between antecedent and consequent event-types.
1.3 The cases of uniform conjunction between antecedent and consequent warrant and/or cause full assurance/full proof.
1.4 Cases of anything less: The evidence of non-uniform events yields only probability:
1.4.1 procedure for determining the probability of such cases:
126.96.36.199 consider the cases in which events of type A and events of type B are experienced to be conjoined
188.8.131.52 consider the cases in which events of type A obtain without events of type B
184.108.40.206 Deduct the latter from the former.
220.127.116.11 The resultant ratio maps onto the probability and degree of assurance with respect to the event.
18.104.22.168 Full uniformity cases = proofs; any other type of case has some degree of probability, from very high to very low, depending on the frequency with which the two types of events are conjoined.
1.4.2 But if there is this range/spectrum, then the wise man proportions his belief according to the evidence; he doesn’t give full assurance to every experienced conjunction of events of type A and type B.
1.5 Experiential evidence of testimony in particular
1.5.1 The justification of testimony (i.e., as a reliable source of information): experienced conjunction between testimonial reports and verification of the facts reported: S testifies that p, and I observe that p is in fact the case.
1.5.2 As testimonial evidence is founded on experience, it, like any other kind of experiential evidence, runs the range from proof to probability: some types of testimony cases are uniformly true, and others are less than uniform.
1.6 Some causes of contrariety of accurate and inaccurate testimony reports, (and so) causes of testimony to be merely probable.
1.6.1 Problems with the testifier(s):
1.6.2 conflicting reports
1.6.3 the character/quality of the witnesses
1.6.4 the quantity of witnesses
1.6.5 the manner in which the witness reports the fact
1.6.6 a combination of two or more of the above
1.6.2 Problems with the event testified to:
22.214.171.124 when the event reported is unusual:
126.96.36.199.1 in general: the stronger evidence destroys the weaker, and the “winning evidence” is diminished in proportion to the degree/extent of the defeated evidence.
188.8.131.52.2 in cases in which the quality and quantity of testimony is also (apparently) impeccable: “proof against proof” cases.
184.108.40.206.2.1 Mutual destruction of the opposing
220.127.116.11.2.2 The stronger of the two proofs prevails.
18.104.22.168 types of unusual events:
22.214.171.124.1 marvelous events: not contrary to experience, but also not conformable with it.
126.96.36.199.2 miraculous events: violations of laws of nature
2. The argument against the rationality of testimony-based belief in miracles
2.1 Laws of nature are matters of fact for which we have uniform experience of events of one type constantly conjoined with events of another type
2.2 But miracles are, by definition, violations of laws of nature – they’re events that go against our uniform experience
2.3 Miracles are, then, events against which there is a full proof from experience.
2.4 Therefore, (by our principle above) if the evidence from testimony for a miracle is to prevail against the full proof from experience against miracles, it must be a stronger proof.
2.5 (General maxim:) (i) This requires that it would be more of a miracle that the testimony is false, than that the miracle that the testimony reports didn’t occur. (ii) Even if it is, its evidence must be diminished in proportion to the strength of the proof against it.
Section X, Part II
2.6 But, in actual fact, there has never been testimonial evidence for a miracle that amounted to a full proof; no miracle satisfies the maxim. This is seen in light of the following four lines of reasoning:
2.6.1 Reason #1: Insufficient quantity and quality of testimony: the basic argument:
188.8.131.52 The testimony for a miraculous event M satisfies the general maxim if and only if: (i) there is a sufficiently large group of testifiers for M; (ii) the testifiers all (a) have unquestioned good sense, (b) have education and learning that is sufficient to assure us that they aren’t self-deluded, (c) such that their integrity is so great as to preclude any suspicion that they would try to deceive us, and (d) of such substantial credit and reputation that they would have a lot to lose if they were caught in deceiving others; and (iii) M occurred (a) in such a public manner, and (b) in a part of the world so celebrated, as to make detection of deception unavoidable.
184.108.40.206 No M satisfies clauses (i)-(iii).
220.127.116.11 Therefore, there is no testimony for an M satisfies the general maxim.
18.104.22.168 The testimony for an M is rationally acceptable iff it satisfies the general maxim.
22.214.171.124 Therefore, no testimony for an M is rationally acceptable.
2.6.2 Reason #2: violates general principles of rationality, viz.:
126.96.36.199 (i) unobserved events resemble observed events, (ii) the most frequently observed events/objects are the most probable; (iii) where there are an opposition of arguments, we ought to give preference to the one that has the most experiments in its favor (i.e., to the most frequently observed event/object).
188.8.131.52 but since miracles don’t satisfy these clauses, they flout these principles.
184.108.40.206 oddly, although this maxim is usually followed with respect to testimony of “unusual and incredible” events, when it comes to testimony of miraculous events, pathological mechanisms go into effect among the vulgar, and these subvert these general principles.
2.6.3 Further details on “the known and natural principles of credulity and superstition”: the pathological mechanisms relevant to reason #2:
220.127.116.11 the passion of surprise or wonder
18.104.22.168 its agreeable nature tends to cause belief of reports that cause it (such as is the case with miracle reports).
22.214.171.124 the pride, admiration and delight received by telling such stories.
126.96.36.199 when the love of wonder is attached to the “spirit of religion”: religious persons who are also enthusiasts:
188.8.131.52.1 prone to delusion. “Sees things that aren’t there”
184.108.40.206.2 willing, with the best of intentions, to persevere in perpetuating a falsehood for the sake of promoting a holy cause
220.127.116.11 vanity and self-interest can result in the same effect as the previous.
18.104.22.168 those who hear and evaluate his reports often don’t have the judgment to verify his reports critically and adequately.
22.214.171.124 they are usually willing to suppress principles of sound judgment for “sublime and mysterious subjects”.
126.96.36.199 even when they’re willing to be critical, “passion and heated imagination disturb the regularity of its operations.”
188.8.131.52 “positive feedback loop” of credulity and impudence: “their credulity increases his impudence, and his impudence overpowers their credulity.”
184.108.40.206 religious teachers and preachers often speak eloquently. But eloquence appeals entirely to “the fancy or the affections, captivates the willing hearers, and subdues their understanding”.
220.127.116.11 propagation ensured by “the pleasure of telling a piece of news so interesting, of propagating it, and of being the first reporters of it.” (cf.. the “marriage reports” illustration)
18.104.22.168 men of sense reject testimony of miracles. They conform to the maxim, because they are familiar with the pathology underlying these reports, and so these mechanisms don’t kick in and undermine conformity to the maxim.
2.6.4: Reason #3: the fact that such testimonial reports tend to abound in areas where ignorant, uncivilized, uncultured people live generates a presumption against their probability.
22.214.171.124 Where civilized cultures accept such reports, they always trace back in time to reports from ignorant ancestors.
126.96.36.199 The civilized believe them because of:
188.8.131.52.1 an “inviolable sanction and authority, which always attend received opinions”
184.108.40.206.1 the universal tendency to think that the world operated differently in the past: what doesn't occur in one's own era may have occurred in an earlier one.
220.127.116.11 In reading of the first history of any nation, "we are apt to imagine ourselves into some new world; where the whole frame of nature is disjointed, and every element performs its operations in a different manner, from which it does at present."
18.104.22.168 In reality, the events of the past were not marvelous events, different from the present.
22.214.171.124 People either lied, or were more ignorant and credulous than we are.
126.96.36.199 Notice that recorded history progressively contains fewer and fewer miraculous reports, until we reach the present, where none occur.
188.8.131.52 The diminishing of reports of marvelous and miraculous events through history, up to the present moment (when only few such reports occur) corresponds to the diminishing of ignorance and credulity in society, and the increase of reason and modernity.
2.6.5 an account of the origination and propagation of miraculous stories:
184.108.40.206 someone lies (or is deluded, or mistaken…?) about the occurrence of some unusual, incredible event
220.127.116.11 the credulous and ignorant in the population (especially in remote and barbarous regions) receive the report as true
18.104.22.168 the reasonable among them don’t think the story worth investigating…at least not until so much time has gone by, that it is impossible to disprove
22.214.171.124 Foolish people are “industrious in propagating the imposture”.
126.96.36.199 The previous four factors make it possible for the lie to go on.
188.8.131.52 Later, the factors of distance in time and place from the origination of the story prevent those who hear of it from gaining better information as to what happened, than the fantastic reports they receive.
184.108.40.206 the stories are exaggerated as they are passed down
220.127.116.11 “and thus a story, which is universally exploded in the place where it was first started, shall pass for certain at a thousand miles distance.”
2.6.6 Reason #4: The miracles of the various religions cancel out each other’s epistemic force
18.104.22.168 there are miracle testimonies at the foundation of every religion.
22.214.171.124 They function as verifications of the truth of a religion.
126.96.36.199 Since the religions contradict each other, if we were to assume that any one of the miracle reports of one religion were true, then that religion would be true, and all the other religions would be false. 188.8.131.52 So, the miracle reports of all the other religions must also be false.
184.108.40.206 This logic iterates to each religion, since the evidential force of the miracle testimony for each religion is roughly the same.
220.127.116.11 But if so, then no miracle report is to be believed: they cancel each other out.
18.104.22.168 As the late J.L. Mackie nicely paraphrased Hume’s analogy with respect to this point: “it is as if a lawcourt were presented with, say, twenty witnesses, each of whom was denounced as a liar by the other nineteen.” Mackie, J.L. The Miracle of Theism (Oxford: OUP, 1982), p. 15.