Skip to content

Discussing the Evolutionary Debunking Argument

John Danaher at Philosophical Disquisitions has a blog anyone with an interest in philosophy should be subscribing to. John presents simple argument diagrams and clear analyses of philosophy papers, usually those that deal with philosophy of religion and related topics. Recently he has been discussing an argument by Guy Kahane of Oxford that evolutionary debunking arguments (EDAs) in ethics are problematic. I suggested that I’d like to read his critique of an EDA argument presented by Paul Griffiths and myself, and he has obliged.

Here are the relevant links:

I will reply on John’s blog when I get time.


  1. Jeb Jeb

    Meh. I am in the middle of trying to sort out Gerald of Wales attempted debunking of Jocelyn of Furness’s claim that St Patrick drove all snakes and venomous creatures out of Ireland. Gerald is playing the “historical truth” card and looking to natural history and observation, but his motives seem more complex.

    This will get me utterly sidetracked and take some time to translate. Looks rather interesting!

    • An EDA is a special case of an NDA (naturalistic debunking argument), and the structure is this:

      P1: Claim A relies upon an exclusively non-natural explanation
      P2: There is a natural explanation for belief in A
      P3: When a natural explanation and a nonnatural explanation compete, it is more parsimonious to accept the natural
      C: The non-natural explanation is debunked [Note: not disproven, just undermined]

      If Gerald is giving a natural explanation for that which Jocelyn explains non-naturally, then he has undermined Jocelyn’s explanation. But the nonnatural explanation may yet be true; it is just that it is an unwarranted belief.

      This is quite distinct from what role the nonnatural belief plays, why it is important, and so on, which are a higher-level issue.

      • I’m not entirely happy with this way of getting at the kernel of the argument. Setting aside the fact that the truth of P3 will be highly sensitive to what is meant by saying that something is natural or nonnatural, which arguably can’t be taken for granted for large-scale domains like ethics, it seems a very large step from “It is more parsimonious to accept explanation E1 than to accept explanation E2” to “E2 is debunked” or “Claims based exclusively on E2 are unwarranted” This doesn’t seem to be at all a safe and reliable inference when it comes to parsimony because (1) parsimony is not the only factor to be weighed in determining whether a belief or explanation is warranted; and (2) parsimony admits of different, and not always consistent, measures. Do you really think it plays such a key role in the structure of these kinds of debunking arguments?

  2. Jeb Jeb

    “If Gerald is giving a natural explanation for that which Jocelyn explains non-naturally, then he has undermined Jocelyn’s explanation.”

    Bradon’s point on P3 seems to be in play as Gerald has to take spontaneous generation as a factor at work when reaching his conclusion. But that just makes it more interesting rather than posing any major issues as these can be resolved small scale, case by case.

    This one runs surprisingly late well into the 20th century although the higher-level issue relating to belief are subject to considerable movement.

    The philosophical argument at the end of the day should be testable with enough individual case studies running with the issues. I suspect.

  3. Great little series… I think I need a month to process it all!

Comments are closed.