Philosopher David Hume and Testimony

I’m doing the wonderful online course (MOOC) Introduction to Philosophy at coursera. Part of the assessment is an (optional) short essay. I’ve chosen to answer:

Was David Hume right to think that one should never believe that a miracle has taken place on the basis of testimony?

I answer this question in my essay included below. For the sake of the course, my target audience will be familiar with the philosophical arguments of David Hume and his opposer, Thomas Reid. I do restate their arguments below, so it should stil be possible to follow along.

Feedback welcome!


Topic: Was Hume right to think that one should never believe that a miracle has taken place on the basis of testimony?


David Hume argued that we should not accept that a miracle has take place on the basis of testimony. I believe this is a fair and vaild argument and a good basis for reasoning. I support this belief based on Hume’s arguments and also contemporary understanding of epistimology and psychology. Further, I will refute some of Hume’s contemporary critics, in particular Reid, and his argument for credulity.


David Hume made an argument for a philosophy of “Evidentialism”. He advocated that “a wise man…proportions his belief to the evidence”. “Testimony” is a claim made by another person. Hume arged that we should weigh our belief in the testimony based on how likely it is that the testifier is right. A miracle – by definition – is something that is unusual and unlikely to have occured.

When faced with the extraordinary testimony, we have to decide: did the miracle occur as claimed, or the testimony is wrong. “What is more likely?” Hume invites us to ask. Testimony is alone is only weak evidence in favour of a miracle. On the other hand, we know from experience, that testimony can be false. From there we can conclude that it is more likely the miracle did not occur.

This argument of David Hume can be further supported by an appeal the scienetific prinicple of “Occam’s Razor”: given competing hypotheses, the one that makes the fewest assumptions should be selected. Accepting that a miracle occured would require us to question, or revise, much of what we know about the world. In contrast it is easy to imagine that a witness is presenting false testimony.

In the case of miracles, we can also turn to ideas of cosmologist, Carl Sagan. He is quoted saying, “Extraordinary claims require extraordinary evidence”. We might believe someone claiming to have seen a cow while they were on their way to work. However, if they claim to have seen a flying cow, we should insist on more evidence than just their testimony.

Hume presents his logic in binary terms: a miracle is unlikely, therefore he discards the possibility. I would argue for a more nuanced approach. I agree that testimony alone is insufficient for us to accept the occurence of a miracle. Under such circumstances, we could reckon that there is, say, a 1% chance that the miracle occurred. Perhaps the witness is known to us, and from past experience, we know them to be honest. In this case we may increase our assesment to a 20% chance.

A contemporary of Hume, Thomas Reid argued against Hume’s scepticism of testimony. Reid believes that, in the same way we are hard-wired to believe our senses, we are also hard-wired to trust others. Imagine that our beliefs were only formed by evidence and experience rather than testimony. Ried argues that children, without experience would believe very litle of what they are told. Yet, children tend to be naturally credulous.

Hume counters this by pointing out that being sceptical of testimony isn’t necessarily something we do, but something we should do.

I would further Humes argument by pointing out that children also weigh the testimony they hear. They will be more sceptical of what they learn from stranger than from their parents. Further, it behoves every individual to question any teachings they uncritically accepted as a child. Our beliefs should not be fixed and we should continually revise them as we learn more of the world. As John Maynard Keynes once quipped, “When my information changes, I alter my conclusions. What do you do, sir?”

Reid also makes an appeal to inherent honesty. In the same way that we are naturally creduluous, we are naturally honest. Hume counterargues with examples of dishonesty (people lie out of self interest) and out of ignorance (we may repeat heresay for the sake of a good story).

I would add that people can be lie without realising. In modern times, we have proof that eyewitness accounts are often unreliable.

In conclusion, Hume provides a convincing argument that we should not simply accept testimony of miracles. Contemporary evidence strengthens Hume’s argument and weaken counterarguments against it.