The Argument from Miracles Over the Course of the Last Few Weeks, We Have Discussed Versions of Most of the Central Philosophical Arguments for the Existence of God

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The argument from miracles Over the course of the last few weeks, we have discussed versions of most of the central philosophical arguments for the existence of God.

I think that these arguments are interesting and important. Nevertheless, I think that it is fair to say that most religious believers throughout history have not come to believe in God on the basis of the arguments we have discussed so far. The argument we’ll be discussing today has probably been discussed less by philosophers than the ones we have already covered, but has probably been more inﬂuential in actually convincing people that God exists.

This is the argument from miracles. There is a long tradition in Christianity of thinking that various miracles can provide the basis for belief in the existence of God.

For example, in Chapter 20 of the Gospel of John, after the story of Thomas, John writes:

“Now Jesus did many other signs in the presence of (his) disciples that are not written in this book. But these are written that you may come to believe that Jesus is the Messiah, the Son of God, and that through this belief you may have life in his name.”

The idea seems clearly to be that we can, and should, come to believe on the basis of John’s telling us about the miracles performed by Christ. This idea has been widely accepted; St. Augustine, for example, is quoted as saying that he would not be a Christian but for the miracles.

This raises the question: can the sorts of testimony that we get from St. John give us good reason for believing in God? In our reading for today, Hume argues that this is not possible; Hume’s central claim is that we cannot be justiﬁed in believing in God on the basis of testimony about miracles. This raises the question: can the sorts of testimony that we get from St. John give us good reason for believing in God? In our reading for today, Hume argues that this is not possible; Hume’s central claim is that we cannot be justiﬁed in believing in God on the basis of testimony about miracles.

But before evaluating Hume’s argument, we should try to get a handle on why someone might think that miracles do provide evidence for the existence of God. How might one argue for the existence of God on the basis of miracles? The following rather straightforward argument suggests itself:

The argument from miracles 1. There have been miracles. 2. If there have been miracles, God exists. ______C. God exists. The argument from miracles 1. There have been miracles. 2. If there have been miracles, God exists. ______C. God exists.

Obviously, the argument is valid, so the only question is whether the premises are true. Hume’s argument focuses on the question of whether we have any good reason to believe premise (1). But let’s focus ﬁrst on premise (2). What, exactly, is a miracle?

According to Hume, a “miracle is a violation of the laws of nature.”

This might seem puzzling. After all, aren’t laws of nature supposed to be universal exceptionless claims? (If we ﬁnd an exception to a supposed law of nature, it seems that the right response is to say that what we thought was a law of nature in fact is not.) And if this is what laws of nature are, isn’t the idea of a miracle just a contradiction? This seems to be a very quick and easy argument against the possibility of miracles. But it is not a very impressive argument. Believers in miracles take there to be moments in history at which God suspends the usual natural order. But because this suspension of the natural order has a supernatural cause, it is natural to think that it is not simply a counterexample to the relevant laws of nature, but rather an exception which, because of the kind of exception it is, does not falsify the law in question for cases in which there is no supernatural intervention.

Aquinas gives a deﬁnition of a miracle which is, for our purposes, more useful. According to Aquinas,

“those things are properly called miracles which are done by divine agency beyond the order commonly observed in nature.”

This is a good a deﬁnition of “miracle” as any, and we will take this to deﬁne the term for our purposes.

If this is the deﬁnition of “miracle”, then premise (2) of our argument is trivially true. The remaining questions are: is premise (1) true? and Do we have any good reason to believe that it is true? Pascal situates the question of miracles within (one part of) the Christian tradition. But the question we want to answer is more general: can miracles play this kind of central role in justifying religious belief of any sort?

We will focus on the question of whether miracles can justify the religious beliefs of people who have not themselves witnessed miracles.

2 Hume’s argument against belief in miracles

Hume thinks that they cannot, and indeed that no rational person would base belief in God on testimony that miracles have occurred. He says: The argument from miracles “. . . therefore we may establish it as a maxim, that no human testimony can have such force as1. There to prove have a miracle, been miracles. and make it a just foundation for any system of religion.”2. If (88)there have been miracles, God exists. ______C. God exists. This is Hume’s conclusion. We now need to understand his argument for it, which begins with some premises about the role of perceptual evidence and testimony in the forming of beliefs. Aquinas gives a deﬁnition of a miracle which is, for our purposes, more useful. According to Aquinas,

“those things are properly2.1 Testimony called miracles and evidence which are done by divine agency beyond the order commonly observed in nature.” Hume’s first claim is that we should base belief on the available evidence: This is a good a definition of “miracle” as any, and we will take this to define the term for our purposes. “A wise man, therefore, proportions his belief to the evidence. . . . He weighs If this is the definitionthe opposite of experiments:“miracle”, then He considerspremise which(2) of sideour isargument supported is by trivially the greater true. The remaining questions are: is premise (1) true?number and of Do experiments: we have any To thatgood side reason he inclines, to believe with that doubt it is and true? hesitation; and when at last he fixes his judgement, the evidence exceeds not what we How could weproperly know callthatprobability premise .”(1) (73-4) is true? Perhaps one could know that (1) is true by witnessing a miraculous event. But let’s assume for now that none of us The general moral seems to be correct: when deciding whether to believe or disbelieve have ever actually witnessed a miracle. Then it seems that our only evidence for (1) is the testimony of people that some proposition, we should weigh the evidence for and against it to see whether it makes do claimthe to proposition have actually or its witnessed negation more a miracle. probable. So, it seems that to see whether we have good reason for believing (1), we have to figure out when we are justified in believing something on the basis of testimony. How does this sort of general principle fit with our practice of basing beliefs on testimony? This is Humeone of has the a central very plausible topics answer:addressed by Hume. Here’s what he has to say about it:

“we may observe, that there is no species of reasoning more common, more useful, and even necessary to human life, than that which is derived from the testimony of men, and the reports of eye-witnesses and spectators. . . . I shall not dispute about a word. It will be suﬃcient to observe, that our assurance in any argument of this kind is derived from no other principle than our observation of the veracity of human testimony, and of the usual conformity of facts to the reports of witnesses.” (74)

2 Pascal situates the question of miracles within (one part of) the Christian tradition. But the question we want to answer is more general: can miracles play this kind of central role in justifying religious belief of any sort?

We will focus on the question of whether miracles can justify the religious beliefs of people who have not themselves witnessed miracles.

2 Hume’s argument against belief in miracles

Hume thinks that they cannot, and indeed that no rational person would base belief in God on testimony that miracles have occurred. He says:

“. . . therefore we may establish it as a maxim, that no human testimony can have such force as to prove a miracle, and make it a just foundation for any system of religion.” (88)

This is Hume’s conclusion. We now need to understand his argument for it, which begins with some premises about the role of perceptual evidence and testimony in the forming of beliefs.

2.1 Testimony and evidence The argument from miracles Hume’s first claim is that we should base belief on the available evidence: 1. There have been miracles. 2. If there have been miracles, God exists. “A wise man, therefore,______proportions his belief to the evidence. . . . He weighs the opposite experiments:C. God exists. He considers which side is supported by the greater number of experiments: To that side he inclines, with doubt and hesitation; and when at last he fixes his judgement, the evidence exceeds not what we How could weproperly know callthatprobability premise .”(1) (73-4) is true? Perhaps one could know that (1) is true by witnessing a miraculous event. But let’s assume for now that none of us The general moral seems to be correct: when deciding whether to believe or disbelieve have ever actually witnessed a miracle. Then it seems that our only evidence for (1) is the testimony of people that some proposition, we should weigh the evidence for and against it to see whether it makes do claimthe to proposition have actually or its witnessed negation more a miracle. probable. So, it seems that to see whether we have good reason for believing (1), we have to figure out when we are justified in believing something on the basis of testimony. How does this sort of general principle fit with our practice of basing beliefs on testimony? This is Humeone of has the a central very plausible topics answer:addressed by Hume. Here’s what he has to say about it:

Hume’s basic idea seems to be this: we believe things on the basis of testimony because, in the past, we have found that testimony is normally correct: normally2 the facts conform to the testimony we receive.

Is Hume right about the fact that we have found testimony to be, usually, correct?

Does this mean that we should always believe whatever we are told? Pascal situates the question of miracles within (one part of) the Christian tradition. But the question we want to answer is more general: can miracles play this kind of central role in justifying religious belief of any sort?

We will focus on the question of whether miracles can justify the religious beliefs of people who have not themselves witnessed miracles.

2 Hume’s argument against belief in miracles

Hume thinks that they cannot, and indeed that no rational person would base belief in God on testimony that miracles have occurred. He says:

“. . . therefore we may establish it as a maxim, that no human testimony can have such force as to prove a miracle, and make it a just foundation for any system of religion.” (88)

This is Hume’s conclusion. We now need to understand his argument for it, which begins with some premises about the role of perceptual evidence and testimony in the forming of beliefs.

2.1 Testimony and evidence

Hume’s ﬁrst claim is that we should base belief on the available evidence:

“A wise man, therefore, proportions his belief to the evidence. . . . He weighs the opposite experiments: He considers which side is supported by the greater number of experiments: To that side he inclines, with doubt and hesitation; Pascal situatesand when the at question last he ﬁxes of miracles his judgement, within the(one evidence part of) exceeds the Christian not what tradition. we But the questionproperly we callwantprobability to answer.” (73-4) is more general: can miracles play this kind of central role in justifying religiousThe belief argument of any from sort? miracles WeThe will general focus on moral the question seems1. There to of be whetherhave correct: been whenmiracles miracles. deciding can justify whether the to religious believe or beliefs disbelieve of people some proposition, we should weigh the evidence for and against it to see whether it makes who have not themselves2. witnessedIf there have miracles. been miracles, God exists. the proposition or its negation______more probable. How does this sort of generalC. God principle exists. ﬁt with our practice of basing beliefs on testimony? Hume has a very2 plausible Hume’s answer: argument against belief in miracles

Hume thinks“we may that observe, they cannot, that there and is indeed no species that of no reasoning rational more person common, would more base belief in The argumentGod on from testimonyuseful, miracles and that even necessarymiracles haveto human occurred. life, than He that says: which is derived from the testimony of men, and the reports of eye-witnesses and spectators. . . . I shall 1. There have beennot dispute miracles. about a word. It will be suﬃcient to observe, that our assurance 2. If there have inbeen any miracles, argument God of this exists. kind is derived from no other principle than our ______“. . . therefore we may establish it as a maxim, that no human testimony can haveobservation such force of asthe to veracity prove of a humanmiracle, testimony, and make and it of a the just usual foundation conformity for any C. God exists. systemof facts of to religion.” the reports (88) of witnesses.” (74)

Hume’s basic idea seems to be this: we believe things on the basis of testimony because, in the past, we have Hume’sThis basic is Hume’s idea seems conclusion. to be Wethis: now we believe need to things understand on the his basis argument of testimony for it, whichbecause, begins in the past, we have found that testimony is normally correct: normally2 the facts conform to the testimony we receive. foundwith that some testimony premises is normally about the correct: role of normally perceptual the facts evidence conform and testimonyto the testimony in the we forming receive. of beliefs. Is Hume right about the fact that we have found testimony to be, usually, correct? Does this mean that we should always believe whatever we are told? This can’t be right, since we are sometimes toldDoes contradictory this mean that things. we should And, in always any case, believe Hume whatever does not we think are told?that we should always accept testimony. 2.1 Testimony and evidence No. Testimony is just one piece of evidence among others. And in cases in which testimony contradicts some of Testimony is just one piece of evidence among others. And in cases in which testimony contradicts some of our our evidence,Hume’s ﬁrst we claim have isto thatdetermine we should which base piece belief of onevidence the available is stronger evidence:: evidence, we have to determine which piece of evidence is stronger:

“A wise man, therefore, proportions his belief to the evidence. . . . He weighs the opposite experiments: He considers which side is supported by the greater number of experiments: To that side he inclines, with doubt and hesitation; and when at last he ﬁxes his judgement, the evidence exceeds not what we properly call probability.” (73-4)

This Thesuggests general the moral following seems rule: to be correct: when deciding whether to believe or disbelieve some proposition, we should weigh the evidence for and against it to see whether it makes the proposition or its negation more probable. We should only believe testimony about the occurrence of some event E if the Howprobability does this sort of the of generaltestimony principle being ﬁttrue with is higher our practice than the of basingprobability beliefs of E’s on testimony?not occurring. Hume has a very plausible answer:

We will focus on the question of whether miracles can justify the religious beliefs of people who have not themselves witnessed miracles.

2 Hume’s argument against belief in miracles

Hume thinks that they cannot, and indeed that no rational person would base belief in The argumentGod on from testimony miracles that miracles have occurred. He says: 1. There have been miracles. 2. If there have been miracles, God exists. ______“. . . therefore we may establish it as a maxim, that no human testimony can have such force asThe to argument prove a miracle, from miracles and make it a just foundation for any C. God exists. system of religion.”1. There (88) have been miracles. 2. If there have been miracles, God exists. ______This is Hume’s conclusion. We now need to understand his argument for it, which begins Hume’s basic idea seems toC. beGod this: exists. we believe things on the basis of testimony because, in the past, we have foundwith that some testimony premises is normally about the correct: role of normally perceptual the facts evidence conform and testimonyto the testimony in the we forming receive. of beliefs. Hume’sDoes thisbasic mean idea thatseems we toshould be this: always we believe believe things whatever on the we basis are told? of testimony This can’t because, be right, in since the past,we are we sometimes have told contradictory things. And, in any case, Hume does not think that we should always accept testimony. found that testimony is normally correct:2.1 normally Testimony the and facts evidence conform to the testimony we receive. Testimony is just one piece of evidence among others. And in cases in which testimony contradicts some of our Testimony is just one piece of evidence among others. And in cases in which testimony contradicts some of our evidence,Hume’s we have ﬁrst to claim determine is that which we should piece base of evidence belief on the is stronger available: evidence: evidence, we have to determine which piece of evidence is stronger:

“A wise man, therefore, proportions his belief to the evidence. . . . He weighs the opposite experiments: He considers which side is supported by the greater number of experiments: To that side he inclines, with doubt and hesitation; and when at last he ﬁxes his judgement, the evidence exceeds not what we properly call probability.” (73-4)

ThisThis suggests Thesuggests general the followingthe moral following seemsrule rule:about to be when correct: we should, when decidingand should whether not, believe to believe testimony or disbelieve about some event occurring:some proposition, we should weigh the evidence for and against it to see whether it makes the proposition or its negation more probable. We should only believe testimony about the occurrence of some event E if the Hume’s principle about testimony Howprobability does this sort of the of generaltestimony principle being ﬁttrue with is higher our practice than the of basingprobability beliefs of E’s on testimony?not occurring. Hume has a very plausible answer: We should not believe that M happened on the basis of the testimony unless the following is the case: “we may observe, that there is no species of reasoning more common, more useful, and even necessaryThe probability to human of the life, testimony than that being which false is derived< the from the testimony of men,probability and the reports of M occurring. of eye-witnesses and spectators. . . . I shall not dispute about a word. It will be suﬃcient to observe, that our assurance in any argument of this kind is derived from no other principle than our observation of the veracity of human testimony, and of the usual conformity of facts to the reports of witnesses.” (74)

2 The argument from miracles 1. There have been miracles. 2. If there have been miracles, God exists. ______C. God exists.

Hume’s basic idea seems to be this: we believe things on the basis of testimony because, in the past, we have found that testimony is normally correct: normally the facts conform to the testimony we receive. The argument from miracles This suggests the following rule about when we should, and should not, believe testimony about some event occurring:1. There have been miracles. 2. If thereOne have conclusion: been miracles, testimony God is exists. one, but not the only, source of evidence which we should use ______when forming a belief. TestimonyHume’s principle is relevant about because testimony it has a (relatively) high probability C. God exists.of being true. But, like any evidence, this can be overridden by other sources of evidence (like, for example,We should contrary not believe testimony) that which M happened have give on a the high basis probability of to the negation of the propositionthe testimony in question. unless the following is the case:

We should onlyThe believe probability testimony of the about testimony the occurrence being false of

We now need to apply these general points about testimony and evidence to the case of HumeThis applies suggestsmiracles. this principle the One following conclusion explicitly principle seemsto the about tocase follow ofmiracles: miraculous immediately: events:

“That 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 endeavors to establish . . . ” (77)

Suppose we have testimony that some miraculous event M happened. Hume is say that we should not believe that What it wouldThe mean problem for the for falsehood the believer of the in miracles testimony is thatto be miracles, “more miraculous” being departures than the from occurrence the laws of the M happened on the basis of the testimony unless the following is the case: relevant event?of nature, It would seem mean to that be exactly the probability the sorts of of the events testimony which being we should falsenot is evenexpect lower to happen. than the As Hume puts it: probability of the event in question happening. And this is exactly what Hume’s principle about testimony The probability of the testimony being false < the probability of M occurring. should lead us to expect. “A miracle is a violation of the laws of nature; and as a ﬁrm and unalterable This is one experienceplausible reading has established of what it thesewould laws, mean the for proof the falsehood against a of miracle, the testimony from the to be “more miraculous” than the occurrencevery of nature the relevant of the event. fact, is as entire as any argument from experience can possibly be imagined . . . There must be a uniform experience against every We now wantmiraculous to know event,why Hume otherwise thinks the that event a principle would not of this merit sort that shows appellation.” that we are (76- never justiﬁed in believing testimony about7) miracles.

The implied question is: could testimony ever provide strong enough evidence to override our massive evidence in favor of nature’s following its usual course (which is also evidence against the occurrence of the miracle)?

2.3 The relevance of religious diversity

In II, Hume adds another reason to be skeptical about testimony about miracles, when he§ writes

“there is no testimony for any [miracles] . . . that is not opposed by an inﬁ- nite number of witnesses; so that not only the miracle destroys the credit of testimony, but the testimony destroys itself. To make this better understood, let us consider, that, in matters of religion, whatever is diﬀerent is contrary . . . Every miracle, therefore, pretended to have been wrought in any of these religions (and all of them abound in miracles) . . . has the same force . . . to overthrow every other system.” (81)

Is this best construed as a separate argument against miracles, or as part of the argument sketched above? If the latter, how does it ﬁt in?

3 The argument from miracles

1. There have been miracles. Pascal situates the question of miracles within (one part of) the Christian tradition. But 2. If thereOne have conclusion: been miracles, testimony God is exists. one, but not the only, source of evidence which we should use ______the question we want to answer is more general: can miracles play this kind of central when forming a belief. Testimony is relevant because itHume’s has a (relatively) principle highabout probability testimony The argumentrole from in justifying miracles religious belief of any sort? C. God exists.of being true. But, like any evidence, this can be overridden by other sources of evidence We should not believe that M happened on the basis of 1. There have(like,We been will for miracles. focus example, on the contrary question testimony) of whether which miracles have cangive justify a high the probability religious to beliefs the negation of people 2. If there haveof thebeen proposition miracles, inGod question. exists. the testimony unless the following is the case: ______who have not themselves witnessed miracles. C. God exists. We should only believe testimony about the occurrenceThe probability of some of the event testimony E if the being false < the 2.2 Testimony aboutprobability miracles of M occurring. probability of the2 testimony Hume’s argumentbeing true is against higher than belief the in probability miracles of E’s not occurring. We now need to apply these general points about testimony and evidence to the case of HumeThis applies suggestsmiracles.Hume this thinksprinciple the One following that conclusion explicitly they principle cannot, seemsto the about tocase and follow indeedofmiracles: miraculous immediately: that no events: rational person would base belief in God on testimony that miracles have occurred. He says: The argument from miracles Hume’s principle about testimony. “That no testimony is sufficient to establish a miracle, unless the testimony 1. There havebe“. been . of . therefore such miracles. a kind, we may that itsestablish falsehood it as would a maxim, beWe more thatshould miraculous, no not human believe than testimony that the M fact, happened can on the basis of the 2. If there havewhich been it endeavorsmiracles, God to establish exists. . . . ” (77) ______have such force as to prove a miracle, and maketestimony it a justunless foundation the following for any is the case: system of religion.” (88) C.Suppose God exists. we have testimony that some miraculous event M happened. Hume is say that we should not believe that What it wouldThe mean problem for the for falsehood the believer of the in miracles testimony is thatto be miracles, “more miraculous” beingThe probability departures than of the from the occurrence testimony the laws ofbeing the false < the M happened on the basis of the testimony unless the following is the case: relevant event?of nature, It would seem mean to that be exactly the probability the sorts of of the events testimony which being weprobability should falsenot is of evenexpect M occurring. lower to happen. than the AsThis Hume is Hume’s puts it: conclusion. We now need to understand his argument for it, which begins probability of the event in question happening. And this is exactly what Hume’s principle about testimony withThe probability some premises of the about testimony the role being of perceptualfalse < the evidenceprobability and of testimonyM occurring. in the forming should lead usof beliefs.to expect. “A miracle is a violation of the laws of nature; and as a firm and unalterable ThisWe now is one want plausible to know reading why Hume of what thinks it would that amean principle for the of falsehoodthis sort shows of the that testimony we are tonever be “more justified miraculous” in believing than We now want to knowexperience why Hume has established thinks that these a principle laws, theof this proof sort against shows athat miracle, we are from never the justified in believing thetestimony occurrence aboutvery of naturemiracles. the relevant of the event. fact, is as entire as any argument from experience can testimony about miracles. 2.1 Testimony and evidence possibly be imagined . . . There must be a uniform experience against every WeTo donow this, want we to need know to whyfigure Hume out how thinks to determinethat a principle the relevant of this sort probabilities: shows that of we the are testimony never justified being false, in believing and of M To do this,not occurring. we needmiraculous to Recall figure the event,out quote how otherwise toabout determine evidence the event the discussed wouldrelevant not probabilities: earlier: merit that appellation.” the probability (76- of the testimony being false, testimonyand theHume’s probability about7) first miracles. claimof the isrelevant that we event should not base occurring. belief onRecall the availablethe quote evidence: about evidence discussed earlier:

The implied“A wise question man, therefore, is: could testimony proportions ever his provide belief to strong the evidence. enough evidence . . . He toweighs override our massivethe opposite evidence experiments: in favor of nature’s He considers following which its side usual is course supported (which by is the also greater evidence againstnumber the occurrence of experiments: of the miracle)? To that side he inclines, with doubt and hesitation; and when at last he ﬁxes his judgement, the evidence exceeds not what we properly call probability.” (73-4) 2.3 The relevance of religious diversity

InTheII, general Hume moral adds another seems to reason be correct: to be skeptical when deciding about testimony whether to about believe miracles, or disbelieve when Hume’s idea§ seems to be this. When we are trying to figure out the probability of some event happening in certain circumstances,hesome writes proposition, we ask: wein the should past, weigh how thefrequently evidence as forthat and event against been it observed to see whether to occur it makes in those circumstances? Our answerthe proposition to this question or its negationwill give us more the probable. probability of the relevant event. “there is no testimony for any [miracles] . . . that is not opposed by an infi- How does this sort of general principle fit with our practice of basing beliefs on testimony? nite number of witnesses; so that not only the miracle destroys the credit of Hume has a very plausible answer: testimony, but the testimony destroys itself. To make this better understood, let us consider, that, in matters of religion, whatever is different is contrary .“we . . Every may miracle, observe, therefore, that there pretended is no species to have of reasoning been wrought more in common, any of these more religionsuseful, and (and even all necessary of them abound to human in life, miracles) than that . . . has which the is same derived force from . . . to the overthrowtestimony every of men, other and system.” the reports (81) of eye-witnesses and spectators. . . . I shall not dispute about a word. It will be sufficient to observe, that our assurance Is thisin best any construed argument as a of separate this kind argument is derived against from miracles, no other or as principle part of the than argument our sketchedobservation above? If of the the latter, veracity how of does human it fit testimony, in? and of the usual conformity of facts to the reports of witnesses.” (74)

3 2 Pascal situates the question of miracles within (one part of) the Christian tradition. But the question we want to answer is more general: can miracles play this kind of central role in justifying religious belief of any sort?

We will focus on the question of whether miracles can justify the religious beliefs of people who have not themselves witnessed miracles.

2 Hume’s argument against belief in miracles

Hume thinks that they cannot, and indeed that no rational person would base belief in God on testimony that miracles have occurred. He says: The argument from miracles Hume’s principle about testimony.

1. There have“. been . . therefore miracles. we may establish it as a maxim,We Hume’s thatshould no not humanprinciple believe testimony about that M testimony happened can on the basis of the The argument2. If there fromhave beenmiracles miracles, God exists. ______have such force as to prove a miracle, and maketestimony it a justunless foundation the following for any is the case: system of religion.” (88) We should not believe that M happened on the basis of 1. ThereC. Godhave exists. been miracles. 2. If there have been miracles, God exists. the testimony unlessThe probability the following of the is testimonythe case: being false < the ______probability of M occurring. This is Hume’s conclusion. We now need to understand his argument for it, which begins C. God exists. The probability of the testimony being false < the with some premises about the role of perceptual evidence and testimony in the forming probability of M occurring. of beliefs. We now want to know why Hume thinks that a principle of this sort shows that we are never justified in believing We nowtestimony want to aboutknow whymiracles. Hume thinks that a principle of this sort shows that we are never justified in believing testimony about miracles. 2.1 Testimony and evidence To do this, we need to figure out how to determine the relevant probabilities: of the testimony being false, and of M To do this,not occurring. we need to Recall figure the out quote how toabout determine evidence the discussed relevant probabilities: earlier: the probability of the testimony being false, and theHume’s probability first claimof the isrelevant that we event should not base occurring. belief onRecall the availablethe quote evidence: about evidence discussed earlier:

“A wise man, therefore, proportions his belief to the evidence. . . . He weighs the opposite experiments: He considers which side is supported by the greater number of experiments: To that side he inclines, with doubt and hesitation; and when at last he ﬁxes his judgement, the evidence exceeds not what we properly call probability.” (73-4)

Hume’s idea seems to be this. When we are trying to figure out the probability of some event happening in Hume’sThe idea general seems moral to be seemsthis. When to be we correct: are trying when to decidingfigure out whether the probability to believe of some or disbelieve event happening in certain certain circumstances,some proposition, we ask: we in should the past, weigh how the frequently evidence as for that and event against been it toobserved see whether to occur it makes in those circumstances?circumstances, Our answer we ask: to in this the question past, how will frequently give us the as probabilitythat event beenof the observed relevant event.to occur in those circumstances? Our answerthe proposition to this question or its negationwill give us more the probable. probability of the relevant event. So, for example,How doesto determine this sort whether of general a principlefair coin flip fit withwill come our practice up heads, of basing we ask: beliefs in the on past, testimony? what percentage of fair coin flipsHume have has come a very up plausible heads? We answer: find that ½ of them have; so we take the event of the next fair coin flip coming up head to have a probability of 50%, or 0.5. “we may observe, that there is no species of reasoning more common, more But this, Hume thinks, is enough to show us that we ought never to believe testimony regarding miraculous useful, and even necessary to human life, than that which is derived from the events. testimony of men, and the reports of eye-witnesses and spectators. . . . I shall not dispute about a word. It will be sufficient to observe, that our assurance in any argument of this kind is derived from no other principle than our observation of the veracity of human testimony, and of the usual conformity of facts to the reports of witnesses.” (74)

2 One conclusion: testimony is one, but not the only, sourceHume’s of evidence principle which about we should testimony use The argument whenfrom formingmiracles a belief. Testimony is relevant because it has a (relatively) high probability of being true. But, like any evidence, this can be overridden by other sources of evidence 1. There have been miracles. We should not believe that M happened on the basis of (like, for example, contrary testimony) which have give a high probability to the negation 2. If there have been miracles, God exists. the testimonyHume’s unless principle the following about testimony. is the case: ______The argumentof the from proposition miracles in question. C. God1. exists.There have been miracles. TheWe probability should not of believe the testimony that M happened being false on < the the basis of the 2. If there have been miracles, God exists.2.2 Testimony aboutprobability miracles of M occurring. ______testimony unless the following is the case: C. God exists. Hume’s idea seemsWe now to need be this. to apply When these we are general trying points to figure about out testimony the probabilityThe and probability evidence of some of to the theevent testimony case happening of being in false < the certain circumstances,miracles. Onewe ask: conclusion in the past, seems how to follow frequently immediately: as that eventprobability been observed of M occurring. to occur in those circumstances? Our answer to this question will give us the probability of the relevant event. “That 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, So, forHume’s example, idea to seems determine to be whether this. When a fair we coin are flip trying will tocome figure up out heads, the probability we ask: in ofthe some past, event what happeningpercentage in certain which it endeavors to establish . . . ” (77) of fair circumstances,coin flips have comewe ask: up in heads? the past, We how find frequentlythat ½ of them as that have; event so beenwe take observed the event to occur of the in next those fair circumstances? coin flip coming up head to have a probability of 50%, or 0.5. Our answer to this question will give us the probability of the relevant event. The problem for the believer in miracles is that miracles, being departures from the laws But this, Humeof thinks, nature, is seem enough to be to exactly show us the that sorts we of ought events never which to we believe should nottestimonyexpect toregarding happen. miraculous events.This, HumeAs Humethinks, puts is enough it: to show us that we ought never to believe testimony regarding miraculous events:

“A miracle is a violation of the laws of nature; and as a ﬁrm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined . . . There must be a uniform experience against every miraculous event, otherwise the event would not merit that appellation.” (76- 7)

Hume’sHume’s point isThepoint that implied is miracles that questionmiracles are always is: are could always departures testimony departures from ever provide thefrom ordinary the strong ordinary laws enough of laws nature. evidence of nature. But to overridethe But ordinary the ordinary laws laws of of nature natureare are regularities regularitiesour massive which which evidence have have been in favorbeen observed of observed nature’s to hold following to hold100% its100% of usual the of coursetime. the timeOf (which course,. Of is course, also we evidence have we nothave observed not testimony to observedbe correct testimonyagainst 100% to the beof occurrence thecorrect time. 100% Hence, of the of miracle)? thethe probabilitytime. Hence, of thetestimony probability regarding of testimony a miracle regarding being false a miracle will always be being greaterfalse will than always the probability be greater of than the themiraculous probability event; of the and miraculous then it follows event; from and Hume’s then it followsprinciple from about Hume’s testimony that we should never accept the testimony. principle about testimony that we should2.3 never The relevance accept ofthe religious testimony. diversity

In II, Hume adds another reason to be skeptical about testimony about miracles, when he§ writes

Is this best construed as a separate argument against miracles, or as part of the argument sketched above? If the latter, how does it ﬁt in?

3 The argument from miracles Hume’s principle about testimony.

1. There have been miracles. We should not believe that M happened on the basis of the 2. If there have been miracles, God exists. Hume’s principle about testimony ______The argument from miracles testimony unless the following is the case: C. God exists. We should not believe that M happened on the basis of 1. There have been miracles. The probability of the testimony being false < the 2. If there have been miracles, God exists. the testimony unless the following is the case: ______probability of M occurring. C. God exists. The probability of the testimony being false < the Pascal situates the question of miracles within (oneprobability part of) the of M Christian occurring. tradition. But Hume’s idea seems to be this. When we are trying to ﬁgure out the probability of some event happening in certain the question we want to answer is more general: can miracles play this kind of central circumstances, we ask: in the past, how frequently as that event been observed to occur in those circumstances? Hume’srole idea in seems justifying to be religious this. When belief we ofare any trying sort? to ﬁgure out the probability of some event happening in Our answercertain tocircumstances, this question wewill ask:give inus the the past, probability how frequently of the relevant as that event. event been observed to occur in those circumstances?We will focus Our answer on the questionto this question of whether will give miracles us the can probability justify the of religiousthe relevant beliefs event. of people Hume’s pointwho is that have miracles not themselves are always witnessed departures miracles. from the ordinary laws of nature. But the ordinary laws of nature are regularitiesHume’s point which is that have miracles been observed are always to holddepartures 100% offrom the the time. ordinary Of course, laws ofwe nature. have not But observed the ordinary testimony laws toof be correctnature 100% are regularities of the time. whichHence, have the probability been observed of testimony to hold regarding 100% of athe miracle time. beingOf course, false willwe havealways not be greaterobserved than the testimony probability to ofbe 2the correct miraculous Hume’s 100% argument ofevent; the time. and against thenHence, it follows the belief probability from in miraclesHume’s of testimony principle regarding about testimony a miracle that we shouldbeing neverfalse will accept always the betestimony. greater than the probability of the miraculous event; and then it follows from Hume’s principle about testimony that we should never accept the testimony. Hume thinks that they cannot, and indeed that no rational person would base belief in God on testimony that miracles have occurred. He says: HenceAnd Hume’s this is conclusion: precisely Hume’s conclusion:

“. . . therefore we may establish it as a maxim, that no human testimony can have such force as to prove a miracle, and make it a just foundation for any system of religion.” (88)

On this reading, Hume’s argument depends upon the following assumption: This is Hume’s conclusion. We now need to understand his argument for it, which begins with some premises about the role of perceptual evidence and testimony in the forming of beliefs. The zero probability principle If some event has never been observed to occur before, then the2.1 probability Testimony of it and occurring evidence is 0%.

Hume’s ﬁrst claim is that we should base belief on the available evidence:

“A wise man, therefore, proportions his belief to the evidence. . . . He weighs the opposite experiments: He considers which side is supported by the greater number of experiments: To that side he inclines, with doubt and hesitation; and when at last he ﬁxes his judgement, the evidence exceeds not what we properly call probability.” (73-4)

The general moral seems to be correct: when deciding whether to believe or disbelieve some proposition, we should weigh the evidence for and against it to see whether it makes the proposition or its negation more probable.

How does this sort of general principle ﬁt with our practice of basing beliefs on testimony? Hume has a very plausible answer:

2 Hume’s principle about testimony The argument from miracles 1. There have been miracles. We should not believe that M happened on the basis of 2. If there have been miracles, God exists. the testimony unless the following is the case: ______C. God exists. The probability of the testimony being false < the probability of M occurring.

On this reading, Hume’s argument depends upon the following assumption:

The zero probability principle

If some event has never been observed to occur before, then the probability of it occurring is 0%.

This is what enables Hume to conclude that we can never be justiﬁed in believing testimony about a miracle, since, as he plausibly assumes, the probability of the testimony being false will always be > 0.

Interestingly, this principle also seems to be enough to establish a stronger claim: one is never justiﬁed in believing in the existence of miracles, even if one is (or takes oneself to be) an eyewitness. Can you see why?

Perceptual experiences of the world, like testimony, don’t conform to the facts 100% of the time. So, the probability of a miraculous event M occurring will always, given the above principle about probabilities, be less than the probability of one’s perceptual experience being illusory, since the latter will always be > 0. Hence, it seems, one would never be justiﬁed in believing in the existence of a miracle, even on the basis of direct perceptual experience.

This might at ﬁrst seem like a good thing for Hume’s argument: it shows not just that one an never believe in miracles on the basis of testimony, but also that one can never believe in them for any reason at all!

But in fact this brings out a problem for the zero probability principle. Hume’s principle about testimony The argument from miracles 1. There have been miracles. We should not believe that M happened on the basis of 2. If there have been miracles, God exists. the testimony unless the following is the case: ______C. God exists. The probability of the testimony being false < the probability of M occurring.

The zero probability principle

If some event has never been observed to occur before, then the probability of it occurring is 0%.

But in fact this brings out a problem for the zero probability principle.

Consider the following sort of example:

You are a citizen of Pompeii in AD 79, and there is no written record of the tops of mountains erupting and spewing forth lava. Accordingly, following the zero probability principle, you regard the chances of such a thing happening as 0%. On the other hand, you know that your visual experiences have been mistaken in the past, so you regard the chances of an arbitrary visual experience being illusory as about (say) 1%. Then you have a very surprising visual experience: black clouds and ash shooting out of nearby Mt. Vesuvius. What is it rational for you to believe? Hume’s principle about testimony The argument from miracles 1. There have been miracles. We should not believe that M happened on the basis of 2. If there have been miracles, God exists. the testimony unless the following is the case: ______C. God exists. The probability of the testimony being false < the probability of M occurring.

The zero probability principle

If some event has never been observed to occur before, then the probability of it occurring is 0%.

Consider the following sort of example:

This sort of case seems to show that the zero probability principle is false. Other such examples involve falsification of well-confirmed scientific theories. So, if Hume’s argument depends on the zero probability principle, it is a failure. But this doesn’t quite mean that Hume’s argument is a failure. Sometimes an argument relies on a false premise, but can be fixed by finding another premise which both avoids the problems with the original one, and still delivers the intended conclusion.

So we should ask: can we come up with another principle, which would avoid these sort of counterexamples while still delivering the result that Hume wants? Hume’s principle about testimony The argument from miracles 1. There have been miracles. We should not believe that M happened on the basis of 2. If there have been miracles, God exists. the testimony unless the following is the case: ______C. God exists. The probability of the testimony being false < the probability of M occurring.

So we should ask: can we come up with another principle, which would avoid these sort of counterexamples while still delivering the result that Hume wants?

It seems that we can. All Hume’s argument needs, it would seem, is the following trio of assumptions:

(a) If some event has never been observed to occur before, then the probability of it occurring is at most X%. (b) The probability of a piece of testimony being false is always at least Y%. (c) Y>X

X does not have to be zero, as the zero probability principle assumes; it is enough for Hume’s argument that it be some number which is always lower than the probability of testimony being false.

Suppose, for example, that the probability of an event of some type which has never before been observed is at most 1%, and that there is always at least a 10% chance of some testimony being false. If we assume Hume’s principle about testimony, would this be enough to deliver the conclusion that we are never justiﬁed in believing in miracles on the basis of testimony?

No, because one can get testimony from multiple witnesses. Suppose that we have three witnesses, each of whom are 90% reliable, and each independently reports that M has occurred. Then the probability of each witness being wrong is 10%, but the probability of all three being wrong is only 0.1%. This, by the above measure, would be enough to make it rational to believe that M happened on the basis of testimony. Hume’s principle about testimony The argument from miracles 1. There have been miracles. We should not believe that M happened on the basis of 2. If there have been miracles, God exists. the testimony unless the following is the case: ______C. God exists. The probability of the testimony being false < the probability of M occurring.

It seems that we can. All Hume’s argument needs, it would seem, is the following trio of assumptions:

(a) If some event has never been observed to occur before, then the probability of it occurring is at most X%. (b) The probability of a piece of testimony being false is always at least Y%. (c) Y>X

So it seems that the possibility of multiple witnesses shows that (a)-(c) are not enough to make Hume’s argument against justiﬁed belief in miracles on the basis of testimony work no matter what values we give to “X” and “Y”. (Of course, it is important to distinguish between having testimony from multiple witnesses and having testimony from a single witness who claims there to have been multiple witnesses.)

But what if we have just one witness. In those cases, won’t Hume’s principle about testimony provide a good argument against the rationality of believing in miracles? Hume’s principle about testimony The argument from miracles 1. There have been miracles. We should not believe that M happened on the basis of 2. If there have been miracles, God exists. the testimony unless the following is the case: ______C. God exists. The probability of the testimony being false < the probability of M occurring.

But what if we have just one witness. In those cases, won’t Hume’s principle about testimony provide a good argument against the rationality of believing in miracles?

Even this can be called into question, because there is good reason to doubt whether Hume’s principle about testimony is itself true.

This principle can sound sort of obvious; but it isn’t, as some examples show. First, what do you think that the probability of the truth of testimony from the writers of the South Bend Tribune would be?

Let’s suppose that you think that it is quite a reliable paper, and that its testimony is true 99.9% of the time, so that the probability of its testimony being false is 0.1%. Now suppose that you read the following in the South Bend Tribune:

“The winning numbers for Powerball this weekend were 1-14-26-33-41-37-4.”

What are the odds of those being the winning numbers for Powerball? Well, the same as the odds of any given combination being correct, which is 1 in 195,249,054. So the probability of the reported event occurring is 0.0000005121663739%. So, if Hume’s principle about testimony is correct, one is never justiﬁed in believing the lottery results reported in the paper, or on the local news, etc. But this seems wrong: one can gain justiﬁed beliefs about the lottery from your local paper, even if it is the South Bend Tribune.

You may want to think about how, if at all, Hume’s principle could be modiﬁed to avoid these counterexamples. Hume’s principle about testimony The argument from miracles 1. There have been miracles. We should not believe that M happened on the basis of 2. If there have been miracles, God exists. the testimony unless the following is the case: ______C. God exists. The probability of the testimony being false < the probability of M occurring.

You may want to think about how, if at all, Hume’s principle could be modiﬁed to avoid these counterexamples.

If it cannot be ﬁxed, then Hume fails to show that it is never rational to believe in miracles on the basis of testimony.

This, of course, does not show that we are currently rational to believe in miracles on the basis of the sorts of testimony we might use as evidence. To decide this question, at least three further issues would need investigation.

1. What are the rules which govern rational acceptance of testimony? If Hume’s principle about testimony is not right, then what is?

2. How good is the evidence for events which seem to be exceptions to the usual natural order? This would involve historical investigation into questions like the following: How many witnesses were there? How reliable were those witnesses? Did they have anything to gain by lying? Etc.

3. When is good evidence that some event is an exception to the usual natural order also good evidence of supernatural intervention?

These are all very difﬁcult questions to answer. What I think the discussion of Hume shows is that to decide the relevance of miracles to religious belief, questions like these are the important ones. There is no argument - at least no obvious argument - of the sort Hume sought against belief in miracles.