sbchan
10-25-2006, 11:42 AM
AT A GLANCE: MIRACLES
1. Defining Miracles
• Problem: if laws of nature are exceptionless regularities and if miracles are exceptions to laws of nature, then miracles are impossible.
• Solution: define laws of nature as regularities that hold when no intervention from outside nature occurs.
2. Hume’s Position
• Hume believed he had discovered “an everlasting check” against accepting reports of miracles.
2.1. Hume’s Argument
1. A miracle is a violation of a law of nature.
2. To count something as a law of nature, we need very strong evidence.
3. A miracle is a violation of a law of nature.
4. Therefore, for something to count as a possible miracle, the evidence against it must be very strong.
5. The probability that a witness might be lying, exaggerating, or confused is always much higher than the probability that the law of nature was violated.
6. Therefore, a witness’s testimony can never make it likely that a miracle occurred.
2.2. Hume’s Argument in Probability Terms
1. The prior probability of any miracle is always low.
2. The relevance of testimony for the miracle is always low.
3. Therefore, the posterior probability of the miracle in light of the testimony is always low.
3. Witnesses
• Objection: Hume overstates the unreliability of witnesses.
• Some potential witnesses are extremely careful and extremely unlikely to lie or exaggerate.
• Reply: miracles are so improbable that even the best witnesses couldn’t establish them.
4. Probability of Miracles
• The claim that miracles are intrinsically improbable isn’t as strong as it appears.
4.1. Strong evidence for laws of nature doesn’t automatically make miracles improbable:
• A miracle is a supernatural intervention.
• Laws of nature are regularities that occur apart from supernatural intervention.
• Evidence for a law of nature is evidence based on how nature behaves when God doesn’t intervene.
• Therefore, evidence for laws of nature tells us nothing about how common miracles are.
4.2. Hume Begs the Question
• When he says that no one has ever seen a dead man come back to life, Christians will not agree.
4.3. Theoretical Arguments
• If there are good reasons to believe in God aside from miracles, then those reasons would raise the general probability of miracles.
5. What If Miracles Are Improbable?
5.1. Lotteries
• Witnesses can easily establish winning numbers in a lottery, even though the prior probability is low.
• This is because the probability of mistakenly reporting any particular number is very low; for a given number, the chance of a “false positive” is low.
5.2. Miracles
• Low prior probabilities do matter in the case of miracles.
• The reason is that if miracles are very rare, then even a skilled witness has a high probability of “false positives.”
5.3. Independent Witnesses
• The combined testimony of independent witnesses can be powerful.
• This is because the probability of all the witnesses being wrong is extremely low.
6. “Competing” Miracle Stories
• Hume thinks that miracle stories from different religions cancel one another out.
• This ignores the difference between the fact of a miracle occurring and the best religious explanation of the miracle.
• Hume could still be right on a more limited point: using miracle stories from one religion as evidence for that religion is problematic if there are equally credible miracle stories from other religious traditions.
7. Establishing a Miracle
• Establishing a miracle calls for two things:
1. Establishing that the event in question actually occurred.
2. Establishing that it was an act of God.
• It’s possible to describe cases that would do both.
8. A Broader Understanding of Miracles
• In actual religious practice, large-scale miracles might not be terribly important
• A believer might think God can intervene in many ways:
1. Obvious violations of natural laws.
2. Events that might seem natural but are actually divine interventions.
3. Natural events with religious significance “built into” nature.
9. Summary
• Hume’s case is flawed.
• This doesn’t show that miracles are real; we must proceed case-by-case.
• How people assess the evidence will depend on their background assumptions.
• The concept of the miraculous is more complicated than it might seem.
WEB RESOURCES
Hume’s discussion of miracles is in Section X of his Enquiry Concerning Human Understanding, which can be found at http://www.etext.leeds.ac.uk/hume/ehu/ehupbsb.htm.
The Stanford Encyclopedia of Philosophy has a good summary discussion of miracles. Go to http://plato.stanford.edu/entries/miracles
1. Defining Miracles
• Problem: if laws of nature are exceptionless regularities and if miracles are exceptions to laws of nature, then miracles are impossible.
• Solution: define laws of nature as regularities that hold when no intervention from outside nature occurs.
2. Hume’s Position
• Hume believed he had discovered “an everlasting check” against accepting reports of miracles.
2.1. Hume’s Argument
1. A miracle is a violation of a law of nature.
2. To count something as a law of nature, we need very strong evidence.
3. A miracle is a violation of a law of nature.
4. Therefore, for something to count as a possible miracle, the evidence against it must be very strong.
5. The probability that a witness might be lying, exaggerating, or confused is always much higher than the probability that the law of nature was violated.
6. Therefore, a witness’s testimony can never make it likely that a miracle occurred.
2.2. Hume’s Argument in Probability Terms
1. The prior probability of any miracle is always low.
2. The relevance of testimony for the miracle is always low.
3. Therefore, the posterior probability of the miracle in light of the testimony is always low.
3. Witnesses
• Objection: Hume overstates the unreliability of witnesses.
• Some potential witnesses are extremely careful and extremely unlikely to lie or exaggerate.
• Reply: miracles are so improbable that even the best witnesses couldn’t establish them.
4. Probability of Miracles
• The claim that miracles are intrinsically improbable isn’t as strong as it appears.
4.1. Strong evidence for laws of nature doesn’t automatically make miracles improbable:
• A miracle is a supernatural intervention.
• Laws of nature are regularities that occur apart from supernatural intervention.
• Evidence for a law of nature is evidence based on how nature behaves when God doesn’t intervene.
• Therefore, evidence for laws of nature tells us nothing about how common miracles are.
4.2. Hume Begs the Question
• When he says that no one has ever seen a dead man come back to life, Christians will not agree.
4.3. Theoretical Arguments
• If there are good reasons to believe in God aside from miracles, then those reasons would raise the general probability of miracles.
5. What If Miracles Are Improbable?
5.1. Lotteries
• Witnesses can easily establish winning numbers in a lottery, even though the prior probability is low.
• This is because the probability of mistakenly reporting any particular number is very low; for a given number, the chance of a “false positive” is low.
5.2. Miracles
• Low prior probabilities do matter in the case of miracles.
• The reason is that if miracles are very rare, then even a skilled witness has a high probability of “false positives.”
5.3. Independent Witnesses
• The combined testimony of independent witnesses can be powerful.
• This is because the probability of all the witnesses being wrong is extremely low.
6. “Competing” Miracle Stories
• Hume thinks that miracle stories from different religions cancel one another out.
• This ignores the difference between the fact of a miracle occurring and the best religious explanation of the miracle.
• Hume could still be right on a more limited point: using miracle stories from one religion as evidence for that religion is problematic if there are equally credible miracle stories from other religious traditions.
7. Establishing a Miracle
• Establishing a miracle calls for two things:
1. Establishing that the event in question actually occurred.
2. Establishing that it was an act of God.
• It’s possible to describe cases that would do both.
8. A Broader Understanding of Miracles
• In actual religious practice, large-scale miracles might not be terribly important
• A believer might think God can intervene in many ways:
1. Obvious violations of natural laws.
2. Events that might seem natural but are actually divine interventions.
3. Natural events with religious significance “built into” nature.
9. Summary
• Hume’s case is flawed.
• This doesn’t show that miracles are real; we must proceed case-by-case.
• How people assess the evidence will depend on their background assumptions.
• The concept of the miraculous is more complicated than it might seem.
WEB RESOURCES
Hume’s discussion of miracles is in Section X of his Enquiry Concerning Human Understanding, which can be found at http://www.etext.leeds.ac.uk/hume/ehu/ehupbsb.htm.
The Stanford Encyclopedia of Philosophy has a good summary discussion of miracles. Go to http://plato.stanford.edu/entries/miracles