Saturday, May 7, 2011

Griffiths and Wilkins on Evolutionary Debunking Arguments (Part Two)

Would anyone trust in the convictions of a monkey's mind?
(Part One)

This post is the second in a brief series on the paper "When do Evolutionary Explanations of Belief Debunk Belief?" by Paul Griffiths and John Wilkins (GW - again, apologies for the abbreviation). In this paper, GW argue that it is possible to respond to evolutionary debunking arguments (of the sort covered here) by constructing a Milvian Bridge, i.e. showing how truth-tracking can be complementary to evolutionary success.

In the previous entry, I outlined the basic elements of GW's argument. The last thing I discussed was their claim that our commonsense beliefs are not debunked by evolutionary explanations. In other words, their claim that a Milvian Bridge can be constructed to cover commonsense beliefs. The key question now is how much further can the Milvian Bridge be extended. GW argue that it can be extended to cover scientific beliefs, but not ethical or religious beliefs.

Although I agree with GW about scientific and ethical beliefs, I am not entirely convinced by their support for the evolutionary debunking of religious beliefs. My contention is that the argument they offer in defence of scientific beliefs could easily be co-opted by the defender of religious beliefs. Whether I am right in this depends heavily on whether I am correct in my interpretation of the argument they offer in support of scientific beliefs, so I turn to that first.

(Note: I am not going to cover GW's discussion of ethical beliefs since I have covered that topic at length before)

1. From Commonsense to Science 
As noted last time, although we can be reasonably confident that our cognitive mechanisms do not fundamentally mislead us about the nature of the objects and entities with which we interact on a daily basis, the kinds of beliefs we have about such objects have no ultimate ontological significance. This is in stark contrast to scientific beliefs about the nature of such objects and entities (and more besides) which, while maybe not representative of the ultimate truth, are thought to get us a good deal closer to the ultimate level.

How can these scientific beliefs be justified? Surely, even if the proponent of the evolutionary debunking argument accepted GW's point about commonsense beliefs, they could still maintain that scientific beliefs are debunked. Scientific beliefs, they will say, take us beyond the realm of commonsense, and while it may be true that our cognitive mechanisms have evolved to track the truth within the realm of commonsense, this gives us no ground for thinking that those same cognitive mechanisms can extend us beyond that realm.

GW offer two points that count against the debunker's arguments in this regard. The first seems slightly weak, and I don't think GW mean for it to count for much, but I'll mention it anyway. It is that scientific beliefs, unlike the kinds of commonsense or intuitive beliefs that may have some evolutionary salience, are not the product of one organism's innate cognitive mechanisms. Scientific beliefs are cognitive innovations, built upon the shoulders of giants, and spread by cultural diffusion.

I take it that while the possibility of cognitive innovations being spread through cultural diffusion has some significance, it doesn't really count against the debunker's arguments. Why not? Because there are many beliefs spread by cultural diffusion but that might be thought to lack the status of knowledge. Indeed, religious beliefs may be a classic example of this.

GW's second point is rather more interesting and significant. It is that we can be confident in the content of our scientific beliefs because they are arrived at via a method that is itself justified by commonsense standards. GW refer to this as an indirect, as opposed to a direct, Milvian Bridge. I think their argument has a certain amount of appeal. Speaking for myself, I can certainly say that when I first learned about double-blind testing it seemed like an obviously correct process for removing biased or distorted interpretations of experimental results.

Since I think this point has significant ramifications, I want to try to sketch out their reasoning in slightly more formal terms. I call this the "indirect Milvian Bridge argument":

  • (1) Our commonsense beliefs are warranted due to the fact that they are produced by cognitive mechanisms that have evolved to track the truth within the commonsense realm (premise, from previous argumentation).
  • (2) If a set of beliefs X is likely to be warranted, and a set of beliefs Y can be derived using standards set by X, then Y is also likely to be warranted (indirect Milvian bridge principle).
  • (3) Scientific beliefs can be derived using standards set by commonsense beliefs.
  • (4) Therefore, scientific beliefs are likely to be warranted.

I hope this is an accurate reflection of GW's argument. Note that the content of scientific beliefs need not be consistent with commonsense, all that matters is that the method used to derive those beliefs is consistent with commonsense. Indeed, scientific beliefs are quite often counter-intuitive.

2. Debunking Religious Beliefs
As noted in the intro, I'm going to skip over GW's discussion of ethical beliefs. One point worth noting is that GW endorse the view held by Street and Kahane that a possible response to evolutionary debunking arguments in ethics is to reject realist conceptions of ethical truth. This endorsement is significant because GW query at the end of their article whether a similar strategy might be available to the religious believer. But I'll leave this issue to the side in order to focus solely on their argument that religious beliefs are debunked by evolutionary explanations.

GW support this argument by reference to some of the leading theories on the evolutionary origin of religious beliefs. Broadly speaking, there are two main categories of such theories (i) those that maintain that religious beliefs confer some sort of evolutionary benefit; and (ii) those that maintain that religious beliefs are a by-product of other cognitive mechanisms that conferred some kind of evolutionary benefit. There might also be a third category that combines both of these approaches (i.e. first a by-product, then an adaptation).

An example of a theory belonging to the first category is that of David Sloan Wilson. He argues that religious belief was selected for due to its potential to enhance social cohesion and prosocial behaviour. Examples of theories belonging to the second category would be those of Barrett, Boyer and Atran. They argue, for instance, that belief in a divine agent is a by-product of a cognitive mechanism for detecting agency (sometimes called the "hyper-active agency detection device" or HADD).

GW argue that neither of these theories can be used to support the existence of a Milvian Bridge for religious belief. Why not? Because in neither case is there any suggestion that religious beliefs were the product of truth-tracking processes. In Wilson's case, the beliefs are selected for their social benefits, not for their ability to track the mind-independent truth. In the case of by-product theories, the beliefs are produced by a mechanism with a propensity for making type 1 (false positive) errors.

3. An Objection
Although I am certainly inclined towards their conclusion, I think GW's argument against religious beliefs is a little too quick. In particular, I worry about their dismissal of by-product theories. They seem to accept, too readily, that beliefs in the existence of a divine mind will be the result of a type 1 error by the relevant cognitive mechanism.

Given my earlier formulation of the indirect Milvian bridge argument, it will probably come as no surprise to learn that this forms the backbone of my objection. I'm inclined to ask: If we are allowed to build an indirect bridge from the realm of commonsense to the realm of science, then why can't we build a similar bridge from the realm of commonsense to the realm of the divine? Here's what I have in mind.

First, I presume our beliefs about the existence of other agents are not massively erroneous (i.e. that, even though the rate of type 1 errors might be high, our HADD still picks out real agents more often than not), I do so on the grounds that, following GW's earlier arguments, other agents are part of our commonsense realm and our beliefs in this realm are likely to be truth-tracking.

Given these presumptions, I think it is plausible that our method for identifying agents in the commonsense realm could (maybe using other criteria set by our commonsense beliefs) be used to derive beliefs about the existence of other minds, including the divine mind. To quote Griffiths and Wilkins talking about scientific beliefs:
"If evolution does not undermine our trust in our cognitive faculties, neither should it undermine our trust in our ability to use those faculties to debug themselves - to identify their own limitations, as in perceptual illusions or common errors in intuitive reasoning."
Quite so, but why assume that we can't debug the HADD and still arrive at a belief in the existence of a divine mind? 

I suspect there are two types of response that GW might make to this. 

First, they could argue that they already acknowledge this possibility since they accept (at the very end of their article) that debunking is not disproving and that other reasons could be adduced in support of religious belief. I think that's right, but then I'm forced to wonder why we need the kind of argument that GW offer in support of scientific beliefs. Surely the concern of the debunker in both cases is with the possibility of justifiably moving beyond the commonsense realm; and surely the response, in both cases, is that an indirect Milvian bridge can be built? 

Second, they could argue that the problem with the HADD is that it is, contrary to my presumption, massively erroneous. That might be true too, but then I can't see why this wouldn't undermine their argument in defence of our commonsense beliefs. Surely other agents are part of our commonsense realm, and surely our cognitive mechanisms would have evolved to track the truth about such entities?

Okay, that's all I have to say on this for now. Hopefully, John or Paul might pop-up in the comments and offer some critique of what I've said. 

[Addendum: I'd like to add that I just came across this paper which seems to address the religious belief issue at considerable length.]


  1. Thanks, John, for this careful and accurate analysis of our work. I agree that, in principle, religious belief can be defended using an indirect Milvian bridge. The question is whether the bridge stands up!

    The indirect Milvian bridge for science consists in arguments for adopting scientific mthods, such as double-blind testing, which you mention, or using classical statistics, or building mathematical models. These arguments have to be such as to convince people who are new to those methods and are relying on common-sense in deciding whether to adopt them. There are some fine examples of such arguments in the works of Galileo, and in early probability theorists like Pascal and the Bernoulli's. I think it's fair to say that these arguments have seemed compelling to the all but a vanishingly small proportion of people who have heard them.

    Now, the equivalent arguments for religious belief, or 'debugging the HADD' as John puts it, have proved much less compelling to most people. There are strong elements of the main Western religious traditions which are precisely rejections of many outputs of the HADD as 'superstition' (in contrast to true religion). For example, most mainstream forms of Christanity discourage people from attributing too much of what happens to them to demons or witches. Perhaps the most sophisticated attempt to 'debug the HADD' is the intelligent design movement, but that remains controversial at best.

    So while the there is an indirect Brooklyn Bridge to science, there is at best a shaky rope-bridge - the kind Indiana Jones might find himself crossing just in time - to religion!

  2. I had a long comment but Blogger ate it. So I will merely say that when an alternative to a religious argument (like the one that had Jesus not been resurrected the disciples would not have risked their lives) is available that is natural and does not involve the truth of the religious claim, the warrant we have for the religious belief based on the likelihood of it being true is reduced (not eliminated on pain of a fallacy of affirming the consequent).

  3. Forgive me, but I don't understand the contra-religion argument, not from a religious perspective. (I'm an atheist, but still.)

    There are two kinds of religious approaches to evolution. One is to say that god intervened in at least key parts in evolution, such as the creation of humans. Clearly, in this case the scientific explanations for the evolution of our religious tendencies are unfounded and an EDA stands no chance of undermining religious belief.

    The more interesting case is when evolution is presumed to have proceeded naturally, but to have been Preordained to arrive at the point it has - humans. It then, however, need not reach its ultimate destination by virtue of tracking the truth. Rather, the course is set at the beginning, and Serendipity assures that we ended up with an accurate "sense of divinity" (and, while we're at it - why not add a "moral sense"!). God has set up a complex game with lots of elements that appear, to our limited mind, to be random and unrelated - but ultimately, all the pieces beautifully flow together to reach the truth. Such is the greatness of God's wisdom and foresight.

    EDAs are, from the start, played in the atheist's courtyard. They are inapplicable to the religious one, which in all its forms doesn't accept the Causal Premise - for the theist, belief is ultimately caused by God, and the evolutionary process is at best an intermediary.


  4. If you guys would indulge somebody who was ABD in philosophy twenty some years ago but has followed the field since only as an occasional spectator, I have this question:

    This is a very interesting argument, but what sort of role does evolution play in this account? Do you depend on anything being scientifically robust?

    When we claim that religious beliefs are false but extraordinarily common, we have the task of explaining how it is that so many humans believe these kinds of falsities.

    The evolutionary stories about our cognitive and psychological deep history are speculative stories with far too little evidence to make scientifically sound claims. The best we can do here is spin out stories that are plausible and not incompatible with our evolutionary and other scientific knowledge. A question like: “Under what environmental and cultural conditions would religious belief A, B, Z, or…ZZZ, be adaptive, neutral, or maladaptive for such and such proto-human?” is empirical enough, but what evidence could ever be diagnostic? I don’t see how science could get there.

    The solid arguments against religious beliefs seem to be that beliefs about gods, souls, afterlives, miraculous interventions, and the like are vague, incoherent, inconsistent, lack predictive power, and are no better in these regards now than they were long ago. In contrast, scientific beliefs are extremely detailed, have high coherence and consistency, and continue to increase in predictive power. Further, we produce far better science when we exclude supernatural ideas than when we try to include them.

    So I guess I would claim that the sort of “evolutionary explanations” you refer to are too weak to debunk anything since they are really only “evolutionary speculations”. But such stories do perhaps help illuminate why it is possible that so many people reject solidly established scientific ideas but embrace rather dodgy religious ones.

    With the weakness of this sort of evolutionary account in mind, the question of whether scientific belief could be debunked might yield to an anthropic perspective: if the brains in question have evolved such that they can pose and debate this issue, then they haven’t gone that far off the rails.

  5. John,

    I was hoping that blogger may have put your comment in the spam folder, but unfortunately that doesn't appear to be the case. Sorry about that. I can appreciate the potential frustration.


    There are lot's things I want to say in response, but I'll stick with one line of thought.

    Of course, I agree that the debugging of the HADD is not successful in practice, but it seems to me that in order to establish that we just have to play the typical game of assessing the competing arguments. As a result, I'm wondering what debunking arguments add to the mix.

    I'm approaching this originally from the debate in metaethics. There, it seems like evolutionary debunking arguments have a genuine impact on a certain class of ethical views. Specifically, that of non-natural realists who subscribe to a basically intuitionistic epistemology. Such realists need our intuitive judgments to be basically truth-tracking because these judgments are the foundation of their ethical systems. The argument is less successful against those with alternative metaethical views.

    I suspect something similar is true about the rest of us and our reliance on our commonsense beliefs. These beliefs arise from a reasonably immediate connection with the external world and they provide an anchor point for all other beliefs we might have. Is that not what motivates the indirect Milvian bridge argument? (digression: is there some foundationalist presumption going on here, and is this problematic?)

    Turning to religion, it seems like the debunking argument is going to be most successful against those who subscribe to a basically intuitionistic (or Plantingan) religious epistemology. It's going to far less successful against evidentialists or rationalists because they will appeal to the traditional arguments and try to explain why they should be rationally compelling in the same way that scientific arguments are.

    But there's a serious impediment to the success of the debunking argument against the intuitionistic religious believer (this is mentioned by Yair, above): they will simply reject the causal premise of the debunking argument. That is, they will reject the idea that their cognitive faculties (specifically, the sensus divinitatus) is the product of a massively contingent evolutionary process. As a result, challenges to their belief system that focus on the second premise of the debunking argument are unlikely to move them.

  6. I meant to edit that before I posted it.

    I wanted to add two other things:


    Your point about alternative naturalistic explanations is persuasive to me. But is the idea that preferring naturalistic explanations over supernaturalistic ones would emerge as part of the process of debugging our evolved faculties?


    I was getting confused about all the different bridges mentioned in your comment, but the Indiana Jones reference resonated with me for some reason. In the Temple of Doom Indiana Jones severs the bridge connecting both sides of the gorge, thereby ensuring it is impossible to go back to the side he came from (or was it the other way round, I can't remember exactly).

    I wondered whether something similar might be going on in the case of debugging our evolved cognitive faculties, e.g. that once we build the indirect bridge from commonsense to science we can never return to our buggy pre-scientific view. I guess you reject that notion in your article since commonsense still plays an important role. Nevertheless, the possibility of severing connections with the original foundations of our worldview struck me as being positively Quinean.

    If one could find the name of the bridge in the movie, one could have a new bridging principle....

  7. "That is, they will reject the idea that their cognitive faculties (specifically, the sensus divinitatus) is the product of a massively contingent evolutionary process. As a result, challenges to their belief system that focus on the second premise of the debunking argument are unlikely to move them."

    Is that what Yair was saying? I thought he was saying that, on a theist view, the massively contingent evolutionary process would lead inevitably to sensus divinitatus.

  8. I take it Yair was referring to two different views. One would be interventionist intelligent design; the other would be some brand of theistic evolutionism.

    According to the former view, God has fairly directly designed our cognitive faculties to perceive him. According to the latter view, God chose the process of evolution by natural selection as the means through which to create such a faculty (a more indirect means of achieving the desired end). It seems on either view, the religious believer could claim that God has designed our cognitive faculties and hence we have no reason to worry of the debunking argument (they could do this by appealing to Plantinga's warrant model).

    The debunking argument might work better against the theistic evolutionist since they accept the process of evolution plays out roughly as most mainstream scientists believe it to have played out, but I'm not sure about this. Most theistic evolutionists that I have come across (e.g. Ken Miller or Simon-Conway Morris) think the process is such that it is far less contingent than typically believed and is directed towards particular ends. Many (Gouldian) evolutionists would seem to object to that (e.g. Jerry Coyne).

  9. That's my point alright. I would say "any kind of of interventionist intelligent design, from Young Earth Creationism to interventionalist Theistic Evolution" instead of just "interventionist intelligent design"; and "any kind of Preordained Harmony" instead of "some brand of theistic evolutionism" (which could be confused with interventionalist ones). But that's just details. John got my point right.

  10. OK, got it.

    Per Robin Hanson's "Homo Hypocritus" theory, it might even be the case that evolution will function against truth tracking at a certain level of intelligence.

  11. [JS Allen had left the following comment to this post. It was unfortunately deleted during the Blogger breakdown]

    OK, got it.

    Per Robin Hanson's "Homo Hypocritus" theory, it might even be the case that evolution will function against truth tracking at a certain level of intelligence.