The Argument from Miracles We’Ve Now Discussed Three of the Central Arguments for the Existence of God

Does God exist?

The argument from miracles We’ve now discussed three of the central arguments for the existence of God. Beginning today, we will examine the case against belief in God.

Next time, we’ll begin a discussion of what is by far the most important argument for atheism: the argument that existence of God is inconsistent with the kind of evil we ﬁnd in the world.

Today we will focus on an argument, not against the existence of God, but against a certain very common kind of belief about God: the belief in miracles.

What do I mean by “miracle”? Here’s how Aquinas deﬁnes it:

“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. Today we will focus on an argument, not against the existence of God, but against a certain very common kind of belief about God: the belief in miracles.

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

Most people who believe in God believe that one or another miracle has occurred in human history. Christians believe that Jesus was raised from the dead, and performed various miracles in his life on earth. Many Muslims believe that Muhammad split the moon in response to religious persecution. Christians, Muslims, and Jews all believe in the miracles described in the Torah. Hindus believe in various sorts of miracles, including events of miraculous healing. Buddhists ascribe various miracles to the Buddha, including the ability to ﬂy and read minds. Most people who believe in God believe that one or another miracle has occurred in human history. Christians believe that Jesus was raised from the dead, and performed various miracles in his life on earth. Many Muslims believe that Muhammad split the moon in response to religious persecution. Christians, Muslims, and Jews all believe in the miracles described in the Torah. Hindus believe in various sorts of miracles, including events of miraculous healing. Buddhists ascribe various miracles to the Buddha, including the ability to ﬂy and read minds.

But what evidence do religious believers have that these miracles have really occurred?

For most, the answer to this question is: they believe it on the basis of testimony of witnesses.

In the reading for today, David Hume argues that this is never rational; Hume’s central claim is that we cannot be justiﬁed in believing in God on the basis of testimony about miracles. In the reading for today, David Hume argues that this is never rational; Hume’s central claim is that we cannot be justiﬁed in believing in God on the basis of testimony about miracles.

David Hume was an 18th century Scottish philosopher, and is widely regarded as the greatest English-language philosopher who ever lived.

He wrote his greatest work, the Treatise on Human Nature, when he was 23 years old.

The work on miracles, which we read for today, was not published in Hume’s lifetime. Let’s turn to our key question: can any of us ever rationally believe that a miracle has ever occurred?

Perhaps (though we will find reason to question this later) one could know that a miracle occurred by witnessing a miraculous event. But let’s assume for now that none of us have ever actually witnessed a miracle. Then it seems that our only evidence for miracles is the testimony of people that do claim to have actually witnessed a miracle. So, it seems that to see whether we have good reason for believing in miracles, we have to first figure out when we are justified in believing something on the basis of testimony.

This is one of the central topics addressed by Hume. Here’s what he has to say about it: 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; 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 propositionThis or its is negation one of morethe central probable. topics addressed by How does this sortHume. of general Here’s principle what ﬁt he with has our to practice say about of basing it: beliefs on testimony? Hume has a very plausible answer:

“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 su⇥cient 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)

Hume’s basic idea seems to be this: we believe things on the basis of testimony because, in the past, we have2 found that testimony is normally correct: normally the facts conform to the testimony we receive.

Is Hume right about the fact that we have found testimony to be, usually, correct? 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 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 as to prove a miracle, and make it a just foundation for any C. God exists. Is Hume right about the fact that we have system of religion.”found (88) testimony to be, usually, correct?

Hume’sThis basic is Hume’s idea seems conclusion. Doesto be Wethis:this now wemean believe need that to things understand we should on the his alwaysbasis argument of testimony for it, whichbecause, begins 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. believe whatever we are told? Does this mean that we should always believe whatever we are told? This can’t be right, since we are sometimes told contradictory things. And, in any case, Hume does not think that we should always accept testimony. No. Testimony is just one2.1 piece Testimony of evidence and evidence among others. And, Hume tells us, in cases in which testimony contradicts some of our evidence, TestimonyHume’s is ﬁrstjustwe one claim have piece is to that ofdetermine evidence we should amongwhich base belief pieceothers. on of And the evidence in available cases is in evidence: stronger:which testimony contradicts some of our evidence, we have to determine which piece of evidence is stronger:

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 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 sucient 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’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 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. Does this mean that we should always believe whatever we are told? This can’t be right, since we are sometimes told contradictory things. And, in any case, Hume does not think that we should always accept testimony. 2.1 Testimony and evidence

TestimonyHume’s is ﬁrstjust one claim piece is that of evidence we should among base belief others. on And the in available cases in evidence: which testimony contradicts some of our evidence, we have to determine which piece of evidence is stronger:

This Thesuggests general theThis moral following suggests seems rule: to the be following correct: whenrule about deciding when whether we should, to believe and or disbelieve some proposition,should we not, should believe weigh testimony the evidence about for and some against event it tooccurring: 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’s principle about testimony Hume has a veryWe plausible should answer: not believe that M happened on the basis of testimony unless the probability of the “we may observe,testimony that there being is false no species < the probability of reasoning of more M common, more useful, and even necessary to humanoccurring. 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 sucient to observe, that our assurance Humein any applies argument this of principle this kind explicitly is derived to from the case no other of miraculous principle than events 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 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. Testimony is relevant because 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, contrary testimony) which have give a high probability to the negation of the proposition in question.Hume’s principle about testimony We should not believe that M happened on the We should only believebasis of testimony testimony about unless the the occurrence probability ofof somethe event E if the testimony2.2 being Testimony false < aboutthe probability miracles of M probability of the testimony being trueoccurring. is higher than the probability of E’s not occurring. We now need to apply these general points about testimony and evidence to the case of This suggestsmiracles.Hume the One followingapplies conclusion this principle principle seems about to explicitly follow miracles: immediately: to the case of miraculous events.

“That no testimony is su⇥cient 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)

SupposeThe we problem haveWhat testimony forit would the believer mean that some for in miraclesthe miraculous falsehood is that event of miracles, the M testimony happened. being departures to Hume be “more is fromsay that the we laws should not believe that M happenedof nature, onmiraculous” seemthe basis to be of exactlythan the testimonythe the occurrence sorts unless of events of the the following which relevant we is shouldevent? the case: notIt wouldexpect to happen. As Humemean puts that it: the probability of the testimony being false is even lower The probabilitythan the ofprobability the testimony of the being event false in question < the probability happening. of MAnd occurring. this is “Aexactly miracle what is a violation Hume’s ofprinciple the laws about of nature; testimony and asshould a ﬁrm lead and us unalterable to This is one experienceplausible reading has established of what it thesewouldexpect. 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 dierent 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 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,Hume’s and principle indeed that about no rationaltestimony person would base belief in The argumentGod on from testimony miraclesWe that should miracles not have believe occurred. that He M says: happened on the 1. There have been miracles.basis of testimony unless the probability of the 2. If there have been miracles,testimony God exists. being false < the probability of M ______“. . . therefore we may establish it as a maxim, that no human testimony can have such force as to prove a miracle,occurring. and make it a just foundation for any C. God exists. system of religion.” (88) We now want to know why Hume thinks that a principle of this sort This is Hume’s conclusion. We now need to understand his argument for it, which begins Hume’sshows basic that idea we seems are neverto be this: justified we believe in believing things on thetestimony basis of testimony about miracles. 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. Does thisTo domean this, that we we shouldneed toalways figure believe out whateverhow to wedetermine are told? Thisthe can’trelevant be right, since we are sometimes told contradictory things. And, in any case, Hume does not think that we should always accept testimony. probabilities: the probability2.1 Testimonyof the testimony and evidence being false, and the probability of the relevant event not occurring. Recall the quote about TestimonyHume’s is firstjust one claim piece is that ofevidence evidence we should amongdiscussed base belief others. on earlier: And the in available cases in evidence: which testimony contradicts some of our evidence, we have to determine which piece of evidence is stronger:

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 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 sucient 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)

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

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 propositionHume’s idea or its seems negation to more be probable.this. When we are trying to ﬁgure out the We should only believe testimony about the occurrence of some event E if the probabilityHowprobability does this of sort someof the of generaltestimony event principle happening being ﬁttrue with is in higher our certain practice than circumstances,the of basingprobability beliefs of E’s on we testimony?not ask: occurring. in the Humepast, has ahow very frequently plausible answer: as that event been observed to occur in those circumstances? Our answer to this question will give us the probability of the “we may observe, that there isrelevant no species event. 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 sucient 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 Hume’s idea seems to be this. When we are trying to ﬁgure out the probability of some event happening in certain circumstances, we ask: in the past, how frequently as that event been observed to occur in those circumstances? Our answer to this question will give us the probability of the relevant event.

Suppose we want to determine the probability of a fair coin ﬂip coming up heads.

We ask: in the past, what percentage of fair coin ﬂips have come up heads?

We 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.

In general, to ﬁgure out the probability of some type of event E occurring, we look at the number of situations in which E could have occurred, and divide the number of times E happened by the total number of possibilities.

This, Hume thinks, is enough to show us that we ought never to believe testimony regarding miraculous events. One conclusion: testimony is one, but not the only, source of evidence which we should use when forming 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 (like, for example, contrary testimony) which have give a high probability to the negation The argumentof the from proposition miracles in question. 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.2.2 Testimony about miracles ______testimony unless the following is the case: C. God exists. We now need to apply these general points about testimonyThe and probability evidence of to the the testimony case of being false < the miracles. One conclusion seems to follow immediately: probability of M occurring.

“That no testimony is su⇥cient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, Hume’s idea seems to be this. When we are trying to ﬁgure out the probability of some event happening in certain which it endeavors to establish . . . ” (77) circumstances, we ask: in the past, how frequently as that event been observed to occur in those circumstances? 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 of nature,This, Hume seem to thinks, be exactly is enough the sorts to ofshow events us which that we we ought should nevernot expect to believe to happen. This, HumeAs Hume thinks, puts is enough it: testimony to show us regarding that we oughtmiraculous never toevents. 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’s point is that miracles are always departures from the ordinary laws of nature. But the ordinary laws of nature The impliedHume’s question point is:is that could miracles testimony are ever always provide departures strong enough from evidence the ordinary to override are regularitiesour massive which evidence have been in favor observed of nature’s to hold following 100% its of usual the coursetime. Of (which course, is also we evidence have not observed testimony to be correctagainst 100%laws the ofof occurrence nature.the time. But Hence, of the miracle)?ordinary the probability laws of of nature testimony are regularitiesregarding a whichmiracle have being false will always be greater than the beenprobability observed of the to miraculous hold 100% event; of the and time then. Of it course, follows wefrom have Hume’s not principle about testimony that we should never observedaccept the testimony testimony. to be correct 100% of the time. Hence, the probability of testimony2.3 The regarding relevance ofa miracle religious being diversity false will always be greater than the probability of the miraculous event; and then it follows In II, Hume adds another reason to be skeptical about testimony about miracles, when § from Hume’s principle about testimony that we should never accept the he writes testimony.

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. ______testimony unless the following is the case: C. God exists. The probability of the testimony being false < the probability of M occurring.

Pascal situates the question of miracles within (one part of) the Christian tradition. But Hume’s idea seemsHume’s to be pointthis. When is that we miracles are trying are to ﬁgurealways out departures the probability from of somethe ordinary 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? rolelaws in justifying of nature. religious But the belief ordinary of any laws sort? of nature are regularities which have Our answer to this beenquestion observed will give tous holdthe probability 100% of ofthe the time relevant. Of course,event. we have not We willobserved focus on the testimony question ofto whetherbe correct miracles 100% can of justify the time. the religiousHence, beliefsthe of people Hume’s pointwho is thatprobability have miracles not themselves ofare testimony always witnessed departures regarding miracles. from a miraclethe ordinary being laws false of nature. will always But the be ordinary laws of nature are regularities whichgreater have than been the observed probability to hold of the 100% miraculous of the time. event; Of course, and thenwe have it follows not observed testimony to be correct 100% of the time. Hence, the probability of testimony regarding a miracle being false will always be greater than thefrom probability Hume’s of 2theprinciple miraculous Hume’s about argument event; testimony and againstthen that it follows we belief should from in miracles Hume’snever accept principle the about testimony that we should never accept the testimony. testimony. Hume thinks that they cannot, and indeed that no rational person would base belief in Hence Hume’sGod conclusion: on testimony thatAnd miracles this is have just occurred. what Hume He says: concludes:

“. . . 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:

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

“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 sucient 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 Here Hume seems to be relying on the following reasonable sounding principle:

The zero probability principle If some event has never been observed to occur before, then you should assign that event a probability of 0%.

This principle, plus Hume’s principle about testimony, is all he needs to show that it is never rational to believe that a miracle has occurred on the basis of testimony. The zero probability principle If some event has never been observed to You have never occur before, then you should assign that observed a miracle to event a probability of 0%. occur.

You should assign any miraculous event a The probability of any probability of 0%. piece of testimony being false is always > 0%.

Hume’s principle about testimony We should not believe that M happened on the basis of testimony unless the probability of the You should never believe testimony being false < the probability of M that a miracle has occurring. occurred on the basis of testimony. 1. If some event has never been observed to occur before, then you should assign that event a probability of 0%. (The zero probability principle) 2. You have never observed a miracle to occur. 3. You should assign any miraculous event a probability of 0%. (1,2) 4. The probability of any piece of testimony being false is always > 0%. 5. We should not believe that M happened on the basis of testimony unless the probability of the testimony being false < the probability of M occurring. (Hume’s principle about testimony) ————————————————————- C. You should never believe that a miracle has occurred on the basis of testimony. (3,4,5) The zero probability principle If some event has never been observed to occur before, then you should assign that event a probability of 0%.

Let’s focus in on the ﬁrst premise of this argument.

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? An example of a grid illusion. The zero probability principle If some event has never been observed to occur before, then you should assign that event a probability of 0%.

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 can never believe in miracles on the basis of testimony, but also that one can never believe in them for any reason at all! The zero probability principle If some event has never been observed to occur before, then you should assign that event a probability of 0%.

But in fact this brings out a problem for the zero probability principle, which can be illustrated by 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? The zero probability principle If some event has never been observed to occur before, then you should assign that event a probability of 0%.

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 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. Let’s see if, by examining our earlier version of the argument, we can find a fix of this sort. Suppose that, if you have never observed some 1. If some event has never been observed to occur event to occur, you should before, then you should assign that event a assign it, not 0, but at probability of 0%. (The zero probability principle) most some probability N 2. You have never observed a miracle to occur. — where N is some 3. You should assign any miraculous event a reasonably small number. probability of 0%. (1,2) 4. The probability of any piece of testimony being false is always > 0%. Call this the “low 5. We should not believe that M happened on the basis of testimony unless the probability of the probability principle.” testimony being false < the probability of M occurring. (Hume’s principle about testimony) ————————————————————- Let’s substitute this in for C. You should never believe that a miracle has the zero probability occurred on the basis of testimony. (3,4,5) principle and see what happens. 1. If some event has never been observed to occur Is this argument valid? before, then you should assign that event a probability of N%. (The low probability principle) What would we have to 2. You have never observed a miracle to occur. 3. You should assign any miraculous event a add to make it valid? probability of N%. (1,2) 4. The probability of any piece of testimony being false is always > 0%. 5. We should not believe that M happened on the basis of testimony unless the probability of the testimony being false < the probability of M occurring. (Hume’s principle about testimony) ————————————————————- C. You should never believe that a miracle has occurred on the basis of testimony. (3,4,5) Here is a reasonable attempt. 1. If some event has never been observed to occur before, then you should assign that event a Is this argument valid? probability of N%. (The low probability principle) It is not, because one can 2. You have never observed a miracle to occur. get testimony from 3. You should assign any miraculous event a probability of N%. (1,2) multiple witnesses. 4. The probability of any piece of testimony being Suppose that we have false is always > N%. three independent 5. We should not believe that M happened on the witnesses, each of whom basis of testimony unless the probability of the are 90% reliable, and testimony being false < the probability of M occurring. (Hume’s principle about testimony) each independently ————————————————————- reports that M has C. You should never believe that a miracle has occurred. Then the occurred on the basis of testimony. (3,4,5) probability of each witness being wrong is 10%, but the probability of all three being wrong is only 0.1%. 1. If some event has never been observed to occur before, then you should assign that event a probability of N%. (The low probability principle) The problem is general. 2. You have never observed a miracle to occur. For any nonzero value of 3. You should assign any miraculous event a probability of N%. (1,2) N, a sufficient number of 4. The probability of any piece of testimony being witnesses will always, false is always > N%. given Hume’s principle, 5. We should not believe that M happened on the make it rational to believe basis of testimony unless the probability of the testimony being false < the probability of M in a miracle on the basis occurring. (Hume’s principle about testimony) of testimony. ————————————————————- C. You should never believe that a miracle has occurred on the basis of testimony. (3,4,5) The problem is general. For any nonzero value of N, a sufficient number of witnesses will always, given Hume’s principle, make it rational to believe in a miracle on the basis of testimony.

However, some historically important examples of miracles seem to have had only one, or very few, witnesses. (Note that the response to the previous argument relies, not just on multiple pieces of testimony, but multiple independent pieces of testimony.)

Might an argument of Hume’s sort be used to show that it is irrational for us to believe in miracles of this sort?

Even this can be called into question, because there is good reason to doubt whether Hume’s principle about testimony is itself true. Hume’s principle about testimony We should not believe that M happened on the basis of testimony unless the probability of the testimony being false < the probability of M occurring.

Here’s an example. What do you think that the probability of the truth of testimony from the writers of the South Bend Tribune is?

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.” Hume’s principle about testimony We should not believe that M happened on the “The winning numbers for basis of testimony unless the probability of the Powerball this weekend testimony being false < the probability of M were 1-14-26-33-41-37-4.” occurring.

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. 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.

How good is the evidence for events What are the rules which seem to be When is good evidence which govern rational exceptions to the usual that some event is an acceptance of testimony? If natural order? How many exception to the usual natural Hume’s principle about witnesses were there? How order also good evidence of testimony is not right, then reliable were they? Did they supernatural intervention? what is? have anything to gain by lying? Etc.

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.