“A wise man proportions his belief to the evidence,” David Hume 1748

Table of Contents

1. Argument from Miracles that God Exists
2. Hume’s Essay Of Miracles
3. Hume’s Argument, using Levitation as an Example
4. Hume’s Argument Against Miracles, Group of Witnesses
5. Hume’s Argument, Reconstructed
   1. Main Argument
   2. Auxiliary Argument, for Second Premise
6. Concluding Paragraph of Part I of Of Miracles
7. Raising of Lazarus
8. Addenda
   1. Two Senses of ‘Miracle’
   2. Formulations of Hume’s Principle
   3. A Failed Lottery Counterexample to Hume’s Principle
   4. Substantiation of Hume’s Argument by Bayes Theorem
   5. Testimony and Testimonial Evidence
   6. Not Hume’s Argument

Argument from Miracles that God Exists

• A miracle is an extraordinary event brought about by God intervening in the course of nature.
  • View Senses of ‘Miracle’
• Miracles have occurred.
• Therefore God exists.

Hume’s Essay Of Miracles

• David Hume is ranked among the greatest philosophers, for good reason. His arguments are clear, cogent, and insightful. His writings are memorable.
• He led the Scottish Enlightenment along with his friend Adam Smith, who wrote that Hume was as “approaching as nearly to the idea of a perfectly wise and virtuous man as perhaps the nature of human frailty will permit.”

• Hume’s Of Miracles, published in 1748, is a classic of philosophy and a model of argument.
• In the essay Hume argues that:
  • It is never rational to believe the report of a miracle.

• Hume’s argument combines three ideas:
  • The idea that determining whether the report of an event is true requires weighing the reliability of the report against the evidence the event did not occur.
  • The concept of a miracle
    • View Miracle
  • The concept of a law of nature
    • View Law of Nature

Hume’s Argument, using Levitation as an Example

Here’s Hume’s argument applied to levitation rather than to miracles.

• Suppose a friend who’s into meditation confides in you that once, deep in meditation, he no longer felt the floor beneath him and, opening his eyes, realized he was hovering five feet above the ground, still in the Lotus Position. His body then slowly descended back to Earth
• Is it rational to believe him?
• The competing hypotheses:
  • Your friend is telling the truth and there exists an exception to the Law of Universal Gravitation.
  • Your friend is kidding or honestly mistaken. Perhaps he fell asleep while meditating and dreamt the episode.
• It’s far more likely that your friend is joking or mistaken than the Law of Gravitation has been broken.
• Therefore it’s not reasonable to believe your friend’s claim that he levitated.

Hume’s Argument Against Miracles, Group of Witnesses

• A group of people say they’ve witnessed a miracle.
• Is it rational to believe them?
• The competing hypotheses:
  1. The group is telling the truth and a miracle occurred.
  2. The group is honestly mistaken or made the story up.
• The second hypothesis is far more likely.
  • Miracles
    • A miracle is an extraordinary event brought about by a divinity manipulating or suspending the laws of nature.
    • A miracle therefore violates the laws of nature.
    • The evidence for the established laws of nature is overwhelming, based on a “uniform experience.”
    • Therefore it’s extraordinarily unlikely that a miracle occurred.
  • False Testimony
    • False testimony, on the other hand, is an everyday occurrence. People lie, make things up, are tricked, delusional, or honestly mistaken.
    • It’s therefore far more likely that the witnesses are honestly mistaken or made things up than that an exception to a law of nature occurred.
• Therefore it’s not rational to believe that a miracle occurred based on group’s testimony.
• As Hume put it,
  • “When anyone tells me, that he saw a dead man restored to life, I immediately consider with myself, whether it be more probable, that this person should either deceive or be deceived, or that the fact, which he relates, should really have happened.”

Hume’s Argument, Reconstructed

Main Argument

1. It is rational to believe the report that an event E occurred only if the reliability of the report is stronger than the evidence E did not occur.
2. The reliability of a report of a miracle is always weaker than the evidence it did not occur.
   • Supported by the Auxiliary Argument
3. Therefore it is never rational to believe the report of a miracle.

Auxiliary Argument, for Second Premise

• Miracles
  • A miracle is an extraordinary event brought about by a divinity manipulating or suspending the laws of nature.
    • View Senses of ‘Miracle’
  • A miracle therefore violates laws of nature.
  • The evidence for established laws of nature is overwhelming.
    • For example, no exception has been found to the law of the Conservation of Energy, that the total energy of a physical system remains the same.
  • Therefore the evidence that a reported miracle did not occur is overwhelming.  
• Testimony
  • Testimony, including that of eyewitnesses, is sometimes false.  People lie, make things up, are tricked, delusional, and honestly mistaken.
• Conclusion
  • Therefore the reliability of a report of a miracle is always weaker than the evidence it did not occur.

Concluding Paragraph of Part I of Of Miracles

“The plain consequence is (and it is a general maxim worthy of our attention), 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. And even in that case, there is a mutual destruction of arguments, and the superior only gives us an assurance suitable to that degree of force, which remains, after deducting the inferior.  When anyone tells me, that he saw a dead man restored to life, I immediately consider with myself, whether it be more probable, that this person should either deceive or be deceived, or that the fact, which he relates, should really have happened. I weigh the one miracle against the other; and according to the superiority, which I discover, I pronounce my decision, and always reject the greater miracle. If the falsehood of his testimony would be more miraculous, than the event which he relates; then, and not till then, can he pretend to command my belief or opinion.”

Raising of Lazarus

• According to the Gospel of John Lazarus of Bethany died of an illness and his body put in a tomb.  Jesus of Nazareth arrives in town four days later. Accompanied by Jewish mourners, Jesus has the stone rolled away from the tomb and tells Lazarus to come out.  Lazarus appears, still wrapped in his burial clothes.

• Per Hume, determining whether Jesus really raised Lazarus from the dead means weighing the reliably of the Gospel of John against the evidence that dead people don’t come back to life.

• The Gospels are not historically accurate, Bart Ehrman
  • The authors of the Gospels were Greek-speaking Christians living 35 to 65 years after the events they narrate.  They were not eyewitnesses.
  • The events they write about are based on oral accounts passed down to them.
  • The authors were Christians spreading the Good News, not impartial historians.
  • The Gospel accounts are filled with discrepancies and contradictions.
  • The original texts of the Gospels no longer exist.
  • The modern versions of the Gospels are derived from the original texts by way of the many scribes who, over the centuries, copied the text by hand.  But the copyists added, changed, and deleted text along the way.

• First objection to Hume’s argument:
  • John, having witnessed the miracle himself, merely recounts what he saw.
  • Reply:
    • The disciple John didn’t write the Gospel of John
      • The gospel was written about 65 years after Jesus died. 
      • The names of the gospels were added later; the original Greek does not mention Mark, Matthew, Luke, and John 
    • The raising of Lazarus does not appear in the other gospels.
    • It’s more reasonable to believe the author of the gospel made the story up.
• Second objection to Hume’s argument:
  • Jesus, being the son of God, can perform miracles.  So Hume’s argument doesn’t apply to him.
  • Reply:
    • The key evidence that Jesus is the son of God is that he rose from the dead.  But the Resurrection is an alleged miracle and thus subject to Hume’s argument, meaning it’s not rational to believe Jesus came back to life based solely on the reports in the Bible.
• Third objection to Hume’s argument.
  • The Bible is the inerrant word of God and therefore any biblical account of a miracle is not merely reliable but infallible.
  • Reply:
    • People wrote the Bible, for example:
      • Genesis was written by multiple authors over the course of centuries, the main sources being J (Yahwist), E (Elohist), and P (Priestly).  J refers to God as Yahweh, E refers to God as Elohim.
      • The authors of the Gospels were Greek-speaking Christians living 35 to 65 years after the events they narrate. The accounts that they narrate are based on oral traditions that had been in circulation for decades. The authors were not eye witnesses.
    • Two hypotheses about the ultimate source of what the authors of the Bible wrote.
      • Natural hypothesis:
        • The ultimate source of what they wrote was people, themselves or others.
      • Supernatural hypothesis:
        • The ultimate source of what they wrote was God, who revealed religious truths to the authors.
    • The natural hypothesis is the simpler, more straightforward theory.
    • The burden of proof rests with the proponents of the supernatural theory to show that some parts of the Bible could not have originated from the mind of man.

Addenda

Two Senses of ‘Miracle’

• Primary Sense
  • merriam-webster.com/dictionary/miracle
    • 1: an extraordinary event manifesting divine intervention in human affairs
  • ahdictionary.com/word/search.html?q=miracle
    • 1. An event that appears inexplicable by the laws of nature and so is held to be supernatural in origin or an act of God.
  • Example
    • “The raising of Lazarus is a miracle.”
• Secondary Sense
  • merriam-webster.com/dictionary/miracle
    • 2: an extremely outstanding or unusual event, thing, or accomplishment
  • ahdictionary.com/word/search.html?q=miracle
    • 2. One that excites admiring awe; a wonderful or amazing event, act, person, or thing.
  • Example
    • “It’s a miracle anyone survived the accident.”

Formulations of Hume’s Principle

• Hume’s Principle
  • “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.”
• Formulations
  • In Terms of Evidence
    • It is reasonable to believe that an event E has occurred, based on testimony, only if the evidence that the testimony is true is stronger (better) than the evidence that E did not occur.
    • Testimony establishes that event E occurred only if the evidence that the testimony is true is stronger (better) than the evidence that E did not occur.
  • In Terms of Rational Belief
    • Testimony establishes that event E occurred only if it it is more rational to believe that E occurred based on the testimonial evidence than it is to believe that E did not occur based on the evidence against E.
  • In Terms of Conditional Probability
    • Testimony establishes that event E occurred only if it it is more probable that E occurred given the testimonial evidence than E did not occur given the evidence against E

• ‘Only if’ or ‘if and only if’
  • I read Hume’s Principle as asserting that testimony establishes an event only if Hume’s conditions are met. That is, Hume’s conditions constitute a necessary condition for testimony establishing an event.
  • Others, however, read if and only if where I see only if. That is, Hume’s conditions are both a necessary and sufficient condition for testimony establishing an event.
  • But there’s a problem with the if half of if and only if, that is with Hume’s conditions being a sufficient condition.
    • Alex takes the following test. He’s shown one shade of red for five seconds, then a second shade of red for another five seconds, and then asked whether the shades are the same. The shades are randomly selected so that half the time they’re the same. But Alex gets the right answer 2/3 of the time.
    • Alex has just been shown two shades of red and said they’re the same. It’s thus more probable that the shades are the same given his testimony (2/3) than that the shades are different (1/2) given how they’re selected. But a probability of 2/3 is not sufficient to establish that the shades are the same.

A Failed Lottery Counterexample to Hume’s Principle

• Let
  • E = Ian won the lottery
  • T = The lottery commission stated that Ian won the lottery
• Suppose the probability of winning the lottery is 1 / 1,000,000,000.
• Suppose the probability of the lottery commission making a mistake is 1 / 1,000,000.
• Hume’s Principle is that
  • Testimony establishes that event E occurred only if the probability that E occurred given the testimonial evidence is greater than the probability that E did not occur given the evidence against E
• The probability that E occurred given the testimony of the lottery commission = 999,999 / 1,000,000.
• The probability that E didn’t occur given the evidence against E = 999,999,999 / 1,000,000,000.
• Therefore the probability that E occurred given the commission’s testimony is not greater than than the probability that E did not occur given the evidence against E.
• Therefore if Hume’s Principle is correct, the lottery commission’s testimony does not establish that Ian won the lottery.
• But clearly the lottery commission’s testimony does establish that Ian won the lottery.
• Therefore Hume’s Principle is false.

• The flaw in the argument is that by the time the lottery commission announces a winner, the selection of a winner is a done deal. The one-billionth probability is irrelevant. What matters are the testimonies of the those who witnessed the selection of the winner and perhaps a video tape of the process.
• Suppose the winner is determined by selecting a numbered ball from a rotating cage. Two scenarios:
  • An official selects a ball from the cage and puts it on a table. Five witnesses agree that the number on the ball is 4393943. Thus:
    • It’s reasonable to believe that ball 4393943 was selected.
    • The probability of selecting ball 4393943 is now epistemically irrelevant.
  • An official selects a ball from the cage but accidentally drops it back into the cage, with no one seeing the number.
    • The number of the selected ball is unknown.
    • The probability that ball 4393943 was selected is the probability of selecting ball 4393943. That probability is still epistemically relevant.

Substantiation of Hume’s Argument by Bayes Theorem

• Let’s suppose that people have gathered to witness what has been predicted to be a miracle.
• E = The people said they witnessed a miracle.
  • This is testimonial evidence based on the people’s testimony that they witnessed a miracle.
  • View Testimony and Testimonial Evidence
• H₁ = The reported miracle occurred
• H₂ = The reported miracle did not occur

• P(H₁) = the “prior” probability that the miracle occurred, i.e. the probability of the predicted miracle apart from the report of its occurrence. This probability is very, very low. Let’s say P(H₁) = 1 / 1,000,000,000 = 1 x 10^-9 = 0.000000001
• P(H₂) = 1 – P(H₁) = 999,999,999 / 1,000,000,000

• P(E|H₁) = the likelihood that the people said they witnessed a miracle given that the miracle occurred
  • P(E|H₁) = 1.0
• P(E|H₂) = the likelihood that the people said they witnessed a miracle given that no miracle occurred
  • P(E|H₂) = 0.01, since it’s possible, when no miracle happened, that the people decided to make one up.

• The Online Bayesian Calculator yields:
  • P(H₁|E) = 1 x 10^-7 = 0.0000001
  • That is, the probability that a miracle has occurred based on the testimony of witnesses is very, very low.

• Bayes Theorem thus substantiates Hume’s argument
• The keys to the substantiation:
  • The exceedingly low probability of a miracle.
  • The possibility that people who say they’ve witnessed a miracle either made it up or were honestly mistaken.

• View Bayes Theorem

Testimony and Testimonial Evidence

• Suppose Williams says “I saw Keagan kill Voss.”
• Williams’ testimony is that he saw Kegan kill Voss.
• There is thus testimonial evidence, based on William’s testimony, that Keagan killed Voss, i.e. that Williams said he saw Keagan kill Voss.
• The truth or falsehood of Williams’ testimony is a matter of evidence. He may be lying, unreliable, or honestly mistaken. If Walter’s testimony is discredited, the associated testimonial evidence is rendered null and void.

Not Hume’s Argument

• A miracle is an extraordinary event brought about by a divinity manipulating or suspending the laws of nature.
• A miracle therefore violates laws of nature.
• Laws of nature are true
• Therefore, miracles don’t happen,