That miracles have supernatural origins is true by definition (see below, in PROBABILITY). Miracles, like all events, must have causes, and cause has motive as part of its aspect, as we have already seen. God must have wanted to perform the miracle, else, of course, He would not have done it.
Shapiro, however, says “God’s intentions, desires, habits, and so on are simply not available to us. Whatever we assume about God’s nature is purely speculative—guesses, really.” Both statements are (at least sometimes) false. If Jesus were God, as he claimed, then his intentions, desires, and habits were known and available. Deciding whether the miracle that a man can be God is a separate question. God’s, or Jesus’s, or even the Holy Spirit’s motives are not always plain, of course, but when a man begs Jesus to be made well, and Jesus heals the man miraculously, the motivation is clear.
If Shapiro is not an empiricist, he plays one in the book. Divining God’s attributes and nature, in our limited and fractured way, is the topic of theology and metaphysics (did you see the bad joke?). It can be done, and has. (See this series.) So Shapiro is wrong because he insists on measurement even when it cannot be had. He asks, “But how do we verify assumptions about God’s characteristics and ‘personality’?” How do we verify there are an infinity of numbers? Answer: we do not and cannot verify it. But we all believe it. An empiricist cannot believe it, however, because he cannot verify it. No math for Shapiro, then, nor logic. Also, that we cannot measure God’s attributes, though we can deduce some, is not a refutation that all our deductions are wrong. Instead, empiricism is a fallacy.
Shapiro’s main conclusion is that since, he says, we cannot discern God’s motives, then we “have no justification for believing” in miracles. “[B]ecause,” he says about one instance, “verification of either assumption [about motives] is impossible—we can’t simply ask Oprah to sit down with a divine entity for an interview about it goals and methods—we’re not justified in believing either of them.” And from this supposed lack of knowledge of motive he concludes “inference to supernatural causes is never justified.” That is the gist of the entire book.
Shapiro fails to see that motive can be guessed about some miraculous claims: that motivation is part of the inference to an explanation, when it accounts for the assumed metaphysics and theology. Shapiro assumes his own, but fails to see they are his own. He also did not acknowledge that we cannot always know motives even in mundane events, such as the example which opened this review (ball on table placed by Alice, Bob, or Charlie). Alice could walk in the room and say “I did it”, but Shapiro would have to reject her claim because he did not learn why she did it. With God, we sometimes do know the motive: He tells us. And sometimes we do not. In any case, that we do not does not mean what happened did not happen (if something indeed happened).
That Shapiro has fallen into these errors is because he attempts to divorce his metaphysics, about which he is mainly wrong, from his epistemology, which he misuses.
Shapiro thinks an event’s improbability is what, in part, makes it a miracle: “the more unlikely the occurrence, the more reason to believe that something supernatural is taking place,” and “miracles should be extremely improbable.” His two criteria for miraculous are:
1. Extremely improbable: a miracle should be unlike anything we have seen before. It should be contrary to everything we know about how the world works.
2. Supernatural: a miracle can’t have a natural explanation. It must be the product of supernatural and typically divine agency.
The second criterion is not controversial. The first is incorrect. The problem is, no miracle has a probability: no event does either. Nothing has a probability, not even the roll of a die. That means improbability cannot be used to judge the veracity of a miracle, or of anything.
Probability is only defined with respect to assumed evidence. Miracles, then, are more or less probable depending on the evidence for or against them that it accepted or assumed. It is the same for any event.
It is however easy to see why Shapiro (or anybody) would say why walking on water is improbable. It is because he gathers evidence of his experience and discovers, in relation to that, such events do not often happen, or have never happened (to his knowledge), and that he cannot think of a cause. Gathered, that evidence makes the event improbable. But, at least to to the one doing the act, who knows the cause (in all its aspects), the probability is certain.
Think about a non miracle, like being struck by lightning. Nobody “has” a probability of being struck by lightning. A golfer standing on hillock in a thunderstorm is under different circumstances than an office drone seated as his desk in a skyscraper. Their circumstances differ in ways we know to be related to the causes of lightning, hence their probabilities differ. Indeed, the golfer and drone may be the same man at different times. Probability solely depends on the evidence believed or assumed. If the evidence changes, the probability changes.
Shapiro finally attempts to turn improbability into a reason not to believe miracles, by referencing the base rate fallacy. This is a real fallacy and old saw (regular readers will well recognize it), introduced in every elementary probability book when Bayes’s theorem arrives. How worried should an asymptomatic women, aged 40-60, with no family history of breast cancer, be when the mammogram comes back positive, considering the mammogram is right (say) 99.9% of the time? Not that worried, as it turns out, because conditional on the information assumed the base rate of cancer is small. A positive mammogram adds to the evidence and increases the probability of cancer only a little. The fallacy comes in supposing the probability of cancer is close to the accuracy of the test.
This is applied to claims of miracles by first assuming miracles are rare, and then assuming claims of miracles are imperfect to some degree in the same way medical tests are. Going only by the “base rate” of miracles, the probability of a miracle is small. Add to the evidence a good but possibly imperfect report, and the probability of the miracle does rise, but it still remains small overall. “The absolutely crucial point is that when we are faced with testimony about something very improbable, such as an alien abduction, we have to ask ourselves one question: What is more likely—that the event really happened, as the witness reports, or that some other explanation for the testimony is true?”
This is a fine question which, as Shapiro says, should and must be asked. Notice it relates to cause, both of the purported event but also of the motivation of the reporter. Not everybody who relates a miracle properly interpreted what they saw, and not everybody tells the full truth. It therefore makes sense to examine every claim critically. And it even makes sense, as in the case of alien abductions, to ignore the claim, given the base information that heretofore all such events critically examined have proved false, or were very likely false (given the evidence accumulated in the investigation). This is because, given all past events like this were false or probably false, we judge the probability high that the newest claim will also be false or likely false.
But this does not work for miracles, for three reasons. One, not all claims of miracles have been proven false or likely false; some have been proved true or likely true. Thus, it is worth investigating substantial new claims, and worth ignoring insubstantial ones (like faces in burnt toast; notice how decision is wrapped up in this). Two, since miracles do not have probabilities, they do not have base rates. Their probability only makes sense with respect to assumed evidence. We can assume their near impossibility, making them immune to any report à la Hume, but this becomes a circular argument (a well known criticism). Three, if we were to rule out any report of unlikely events, nobody who (say) claimed (say) to win the lottery could ever be believed (lottery probabilities specify the precise evidence with which to calculate their probabilities).
Shaprio is finally wrong again, because rarity does not define miracles. Every day in tens of thousands of churches, the miracle of transforming nature of bread in the Body of Christ occurs. Another miracle is the universe being held in existence from moment to moment. Rarity doesn’t enter into it.