Tuesday, March 3, 2009

Plantinga's argument against naturalism

I am actually now writing a little paper on Plantinga's argument against naturalism. I'll post a draft here shortly for comments.

46 comments:

Psye said...

Looking forward to it!

Brian said...

Hi Stephen, is that the argument that because we have reliable truth faculties naturalism is wrong?

Stephen Law said...

brian - yes that is the one.

AIGBusted said...

Also looking forward to it!

P.S. Do you think that it would be possible for you to email interested parties a pdf of it when it is published?

Kosh3 said...

As I understand and remember the argument, he argues that because evolution has an interest in producing only efficient, pragmatic cognitive systems, not truth-finding ones, that on the naturalism account truth-based epistemology cannot be justified. Without god, we have no justification for thinking our beliefs are true, just that they are useful (god ensures truth is accessible to our cognitive structures, having designed them or directed them for that purpose).

My point of attack would be to question why there needs to be any great separation between what works and what is true. A belief that works can be a belief that is true - indeed often times we explain why a belief worked precisely because of the fact that it is (presumably) true. The truth can be useful too.

Phaedrus said...

Awesome. Are you supporting it or critiquing it?

Brian said...

If Stephen's supporting it Carte Blanche then I am the worst judge of human nature that's ever existed. I think Stephen will give credit where it's due, but point out the assumptions (premises) that one needs to accept the conclusions of Plantinga's argument are not those that atheists/agnostics/naturalists would share.

Of course, I could be wrong. :)

Stephen Law said...

Yes I am developing a criticism. Of course it might not be good enough to be published....

Geert Arys said...

I searched and found Platinga's argument on Wikipedia, not necessarily the best source but it has to do.

It only confirms my viewpoint about philosophers that it's a bunch of funny guys using expensive words trying to prove nutty stuff using only hot breath. - sorry, Stephen and Alvin.

But philosophy is the one of the few academic domains where simpler folk can have a go at as well, so here I am.

I read:
Beliefs are causally efficacious with respect to behaviour and also adaptive, but they may still be false.
From what understand, this is what I think happens in reality. His three other possibilities about how beliefs work are mere academic musings, I believe.

Since behaviour is caused by both belief and desire, and desire can lead to false belief, natural selection would have no reason for selecting true but non-adaptive beliefs over false but adaptive beliefs.
Yes, this happens with religion. See how many religions and flavors of them there have been in the world? Even Platinga must admit most of them are false, and moreover, he should admit that most have adapted towards the social situation of its adepts.
But no reason is a whole other thing: with technology (and science), evolution has a reason to select true beliefs about that. I think that a caveman hitting another caveman over the head with a better stick will have more chances at survival.

Thus P(R|N&E) in this case would also be low.[8] Plantinga points out that innumerable belief-desire pairs could account for a given behaviour;
Even if there are innumerable belief-desire pairs, that does not give them all the same chances of occurence, let alone survival.

I'll illustrate with the example:

for example, that of a prehistoric hominid fleeing a tiger: Perhaps Paul very much likes the idea of being eaten, but when he sees a tiger, always runs off looking for a better prospect, because he thinks it unlikely the tiger he sees will eat him. This will get his body parts in the right place so far as survival is concerned, without involving much by way of true belief. ... Or perhaps he thinks the tiger is a large, friendly, cuddly pussycat and wants to pet it; but he also believes that the best way to pet it is to run away from it. ... Clearly there are any number of belief-cum-desire systems that equally fit a given bit of behaviour.

Well, the occurence of the example is an evolutionary improbability because we have inherited the fleeing response from less philosophical ancestors.

Moreover, if Paul would have a genetic defect and not flee, he'll have less chance to survive the tiger. Some descendants would stand and discuss hours about the adaptable belief if petting is in fact the same as runnig away. The tiger would have in fact eaten at least some of them, giving his offspring less survival chances.

False beliefs are not without cost in the world. Even right beliefs for the wrong reason (like running is a kind of petting in case of a tiger) is not without cost: if you think that, you'll run away from dogs, thus loosing the evolutionary advantage of having a loyal helper at the hunt.

Many false beliefs will survive, if they have a neglectable cost towards their gains.
All (other) religions (than the one you believe in) is an example there. The gain of easily organising a social structure neglects the cost of it. Especially if the cost is the diabolisation of other opinions. Then it is even self-sustaining.

So what the hell is his argument against naturalism all about? It fits why both science and belief survives.

Sorry, but I think this argument against naturalism has tickled my humoristical cords and made me think more of philosophers. See, I like comedians very much. I really do.

I hope you're not laughing at me now....

Steven Carr said...

PLANTINGA
for example, that of a prehistoric hominid fleeing a tiger: Perhaps Paul very much likes the idea of being eaten, but when he sees a tiger, always runs off looking for a better prospect, because he thinks it unlikely the tiger he sees will eat him.

CARR
So the guy is making logically valid deductions from premises that happen to be incorrect.

That sounds exactly like Plantinga's arguments!

Even on Plantinga's own chosen example, the guy is making a lot of reasoning that is reliable.

'Sees a tiger' . You try programming a computer to read in light data and pick out tigers, lions, grass or trees from the mass of data that is generated when light falls on photo-electric cells.

If the guy's faculties are reliable enough to detect tigers, then they are really advanced in terms of computational ability and information processing.

So Plantinga's point is....?

There is a point in Plantinga's argument - one that I have seen Dennett address.

Just how exactly does the brain know which true beliefs are useful?

Suppose I see a black bomb in a box in the room with me.

Plantinga would tell us that his god has given him the ability to know that it is dangerous to have a black bomb in a box with a room with me.

So the brain generates the true belief that I should try to avoid the situation of having a black bomb in a box in a room with me.

If I paint the bomb red, or lift the bomb out of the box, or carry the box out of the room, it will be a perfectly true belief that there is no longer a black bomb in a box in the same room with me.

But none of those perfectly true beliefs help me avoid being blown up.

So how does the human brain select which true beliefs are useful , without going through the time-comsuming process of wading through all possible true beliefs? (ie if painting the bomb red does not help, will painting the bomb blue help?)

Plantinga's 'true beliefs come from God-designed mechanisms' is utterly useless in answering this question.

These God-designed mechanisms can produce true beliefs all day long until the bomb explodes....

So how does natural selection design brains which know which true beliefs are going to be useful?

This is a mystery.

And if there is a mystery, there is Plantinga ready to jump in with 'God-did-it'....

David B. Ellis said...


My point of attack would be to question why there needs to be any great separation between what works and what is true.


Mine is that the reliability of our faculties, however they formed, are what they are and their reliability (in the ways a naturalist would consider them reliable at all) is empirically testable.

I use my factulties to conclude that one needs X amount of gas in a car that goes Y miles per gallon to get to town A to town B.

Someone puts only half of X in their tank and attempt to make this trip.

I conclude that they will run out of gas halfway there if they make no stops for gas and have no extra gas in their car.

Lo and behold, my faculties (supposedly of low or inscrutable reliability) predicted the outcome with great reliability.

That's the heart of the mistake in Plantinga's reasoning. The reliability of our faculties is TESTABLE and therefore, in those ways that its testable, the reliability is very knowable.

The only things its reliability is low or inscrutable on are questions where its not testable. Things like "Jesus is risen because he lives in my heart" or "Berkeley's idealism accurately describes the nature of reality".

In other words, things like religion and metaphysical theories. The things most of us naturalists never thought were reliable anyway.

Tony Lloyd said...

Steven Carr:So how does natural selection design brains which know which true beliefs are going to be useful?

I don't think much of Plantinga's examples. I much prefer the example of the shape recognition instinct in herring gull chicks (http://books.google.co.uk/books?id=8CQ5U2xKlZMC&printsec=frontcover&dq=common+sense+science+and+scepticism#PPA76,M1), partly because it supports what I want to say! Herring gulls run and hide if a shape made out of cardboard is moved in certain way. The herring gull chick “thinks” (no doubt he doesn't articulate it, but he acts in accordance with it) “anything with shape X, moving in way Y is a hawk”, which is untrue. But the belief means that when it is a hawk the chick hides and has a better chance of survival. “Nothing with shape X, moving in way Y is a hawk” is also false. As this would lead to the chick taking no evasive action when a hawk was around it is not as useful.

So it's not so much a case of Natural Selection selecting useful truths from useless truths, more a case of Natural Selection selecting useful falsehoods from useless falsehoods.

Tony Lloyd said...
This comment has been removed by the author.
wombat said...

Re: Evolving true beliefs.

As many have pointed out false beliefs may assist survival, however we must ask what is the likelyhood that a beneficial false belief will actually carry a greater survival value than a true one?

It seems possible in particular cases but I do not think it is actually correct. Take the example of the hawk shaped piece of cardboard. If we run from all such shapes we will be safe in all cases but we will expend a great deal more energy running as opposed to reproducing or foraging. This possibly very small cost of getting a "false positive" will in time (and we have geological quantities of it) make a difference. The individuals who can spot the difference will do better.

So I think in general that more accurate beliefs will have greater survival value. Hence any species which can increase the accuracy of its beliefs is more likely to prosper

Adaptiveness is itself an adaptation.
A species which can adapt to its environment within an individuals lifespan will have a survival advantage. This must also apply to behavior and since at least some of the behavior arises from the internal model of the world in the form of beliefs there will be an advantage in the creatures mind being able to adapt and improve its beliefs in response to the changing conditions. This provides a greater spur to the evolution of a mechanism for improving the accuracy of belief within the lifetime of the individual.

Brian said...

Since behaviour is caused by both belief and desire, Is it? I thought it had been shown that our brain has already started acting, motor stuff, before we'd even become conscious of our desire to move for example.

Also, doesn't Plantinga have to show that our beliefs are true before he claims they are? They might just be what's useful to survive in any case. ;)

Dr Funkenstein said...

A paper that is worth a read (I think anyway) that I was reading today is by a guy called Omar Mirza from 2007 - it outlines the argument well and discusses some of the objections and responses from Plantinga and others

http://www.springerlink.com/content/718q237555641432/

link to the PDF is here if your institution has a subscription

Geert Arys said...

If God and not nature induces true beliefs, why are there so many false religions?

splittter said...

One thing I have trouble with is working out exactly what the force of Plantinga's argument is. So, even if we accepted it uncritically, how is it a particular problem for naturalism? There are certainly materialist athiests who are quite happy to accept that beliefs produced by empirical enquiry are not 'true' in the sense of corresponding directly to the external world, but only 'true' as being useful in manipulating it to our ends.

Is it because he thinks there's some paradoxial contradiction in that believing evolution gives us cause to doubt it is actually true? Or is it just because he likes the evolutionary hypothesis (and lots of other science) enough to want to be able to say they are definitely 'true' in the stronger sense? Neither seem like a proper criticism to me, just like consequences that Plantinga hopes aren't correct.

wombat said...

In case people missed it the first time around there is an article by Plantinga
here, which says a little about his position that naturalism is self defeating as well as being an entertaining rant against Richard Dawkins.

floyd said...

I can't wait to read it. I remember listening to Plantinga's lecture against materialism where he claimed the soul has no parts. How does he know that the soul doesn't have millions of parts? He also suggested that animals must have some sort of immaterial entity in them as well because he claims that materialism cannot account for thinking beings.

floyd said...

BTW...You can listen to Plantinga's lecture "Against Materialism" for free here --> http://radioapologia.com/archives/Against_Materialism_with_Alvin_Plantinga.mp3

get_education said...

Oh gosh, this Plantinga guy is so full of shit. I guess he has not read any of the comments against his stupid arguments. Nor does he have any lists of fallacies.

The guy is just preaching to the convinced. Nothing else.

G.E.

get_education said...

Hi Tony,

I much prefer the example of the shape recognition instinct in herring gull chicks

Yup, the problem is that there is an underlying "truth" behind that false belief. Oftentimes the shape is a hawk.

The prehistoric man running for completely unrelated reasons from a tiger is what Plantinga wants in his examples. Why? Otherwise his "defeater" of naturalism fails. If he used the hawk example he would be showing that despite underlying unreliability, our cognitive faculties could still help us propose ways of dealing with its problematic nature. No, he wants examples of completely out-of-reality, yet "adaptive", beliefs. So that it looks like, if we are the products of evolution, then we would not be able to trust anything we conclude. Naturalism for example. This is the meat of his "argument".

G.E.

get_education said...

Stephen,

I have a question. Kinda important:

It is qite obvious to me that Pantnga fails, and I cold even point to false assumptions, fallacies, and such. Yet, it also seems like philosophers take seriously shit like that as if it were "academically valid". Is it that, or is it more like an exercise of the bullshit detection system that there is something of a need of a scholarly publication to evidence the kind of crap that spreads around our culture?

It sounds like criticism of your area, but I truly do not get it. The main problem I see is that people like this Plantinga guy, and others I have read have PhDs in philosophy, yet fall for the most obvious trickery (or propose arguments on the basis of the most obvious trickery). Is this normal? Do people get jobs in serious universities despite making argument's like Plantinga's? Would something like the "defeater of naturalism" be published in a serious philosophy journal?

G.E.

Stephen Law said...

Hi Get-education.

Plantinga is v well respected as a philosopher. Rightly so. He is no fool. It takes some effort to figure out where his arguments go wrong.

If having bonkers or highly counter-intuitive or currently highly unpopular theories meant you could not get published, well, that would rule out a lot of philosophy! Wittgenstein and Russell's logical atomisms, Berkeley's Idealism, etc. are all pretty bonkers. Some would say the same about Singer's views on animals.

Alex said...

A lot of the comments have picked up some very telling faults with Plantinga's EAAN, so I thought I'd add something that doesn't seem to have been addressed.

Rather than thinking that R (The reliability of our cognitive faculties) is low under evolutionary naturalism, I think that R is much less likely under theism.

Theism does a pretty poor job of explaining a number of features of the world, such as the existence of apparently unnecessary suffering, or God's apparent hiddenness.

I think, in response to these problems, the best theists can offer is that God has unknown reasons for allowing suffering/nonbelief/etc.

But this answer leads to a more general, pernicious form of skepticism. For instance, God might have unknown reasons for making the Earth appear much older than it is, as young earth creationists claim.

There's no reason to think that God has such reasons, but neither is there any reason to think that God has unknown reasons for allowing suffering. It's taken on faith.

Furthermore, God might have unknown reasons for allowing "epistemic evils", some defect in our cognitive faculties that make most of our beliefs false, or unjustified. In which case, the theist has an undercutting defeater for theism, her belief in which was produced by her faulty cognitive faculties.

anticant said...

Is the existence of the supernatural a testable hypothesis?

anticant said...

"Plantinga is well respected as a philosopher. Rightly so."

With respect, Stephen, may I remind you of Hume's remark in 'The treatise of Human Nature' that

"Whatever has the air if a paradox, and is contrary to the first most unprejudiced notions of mankind is often greedily embraced by philosophers, as showing the superiority of their science, which could discover opinions so remote from vulgar conception."

wombat said...

"Is the existence of the supernatural a testable hypothesis?"

Yes, but the non-existence of it is not, so I suppose it is not a scientific hypothesis.

Now if a supernatural thingey were to turn up and obligingly flout the laws of nature for us we could settle the matter...

Perhaps the spirits obey the laws of nature just because they think it is the right thing to do.

get_education said...

If having bonkers or highly counter-intuitive or currently highly unpopular theories meant you could not get published, well, that would rule out a lot of philosophy! Wittgenstein and Russell's logical atomisms, Berkeley's Idealism, etc. are all pretty bonkers. Some would say the same about Singer's views on animals.

Then it means people like Plantinga are sustained by the failures of the system to distinguish arguments with merit from those without. This happens in my field too, of course. I would think that Plantinga's arguments are not that hard to detect as crappy. Just, maybe, it takes a more serious philosopher to detect the issues than the average person with a degree in philosophy could do.

From what I read at the linked article above, where Plantinga rants against Dawkins, he is more academy-sounding trickery than philosopher. Unless that is also considered philosophy (though that was not a philosophy journal, just a christianity magazine of sorts).

Anyway, thanks for your answer.

G.E.

Anonymous said...

"Plantinga is well respected as a philosopher. Rightly so. He is no fool. It takes some effort to figure out where his arguments go wrong."

Stephen, you're a prize-winning philosopher and I'm not (I'd feel flattered if someone accused me of being a tenth rate mind), but P's argument, as summarised by Brian, brought immediately to mind the crack attributed to Orwell about some ideas being so absurd only an intellectual could believe them.
Kiwi Dave

David B. Ellis said...


It takes some effort to figure out where his arguments go wrong.


My assessment of Plantinga is similar. I've always thought he was a clever sophist. Good at dressing up bad arguments so that it takes some thought to see why they're so very bad.

Not much of a compliment, though, calling a person, in essence, a skilled rationalizer of the ridiculous.

anticant said...

"A skilled rationalizer of the ridiculous" is a spot-on description of a great many theistic sophists [not least Sye].

Such folk don't hold the same fascination for me as they seem to for some professional philosophers. Endlessly tilting at their windmills and straw men strikes me as just boring.

noggin said...

<<"Is the existence of the supernatural a testable hypothesis?"

Yes, but the non-existence of it is not, so I suppose it is not a scientific hypothesis.>>

Not sure about that. I tend to think that if it's testable, it's natural by definition. There's also no way of telling whether something is flouting the laws of nature as they actually are, rather than as we understand them.

A workable definition of "supernatural" would be useful, too.

wombat said...

noggin -

Leaving aside for the moment that I do not believe in the supernatural, the reason I put it that way was that it is usually claimed that supernatural agencies have a sort of free will which allows them to not reveal themselves.
(How convenient for them.)

If you have an imp in a bottle which claims to be able to grant you three wishes it only has to do so once to prove the point. If it just sits there raising endless objections as to why you shouldn't get the wishes on this particular occasion what is to be done?

noggin said...

wombat

I doubt we're in serious disagreement here. I just can't see a viable, or even valid test for the existence of the supernatural. The problem is not empirical, it's conceptual - a matter of what laws, if any, it works by, and how does it interact with the natural?

First, catch your imp...

David B. Ellis said...


Such folk don't hold the same fascination for me as they seem to for some professional philosophers. Endlessly tilting at their windmills and straw men strikes me as just boring.


I can understand that reaction but I find discussions with them surprisingly productive. Dealing with the willfully obtuse has a way of forcing one to clarify one's thinking and means of expression as few other things can.

In that respect presuppositionalists can be very useful.

anticant said...

David - that may well be, but once the repetitive fallacies of such people as Sye - and for that matter Plantinga - have been identified there are much more important and reality-based issues calling for urgent clarification if philosophy is to have any practical relevance..

In any case, much of the discussion we've been having here doesn't clarify but throws around vague concepts such as "truth" without defining them in a meaningful way.

Surely an essential task of philosophy is to use such terms with precision. I am not a professional philosopher, and come here for instruction as well as entertainment. I don't always get either.

Anonymous said...

If anyone is interested, there's been a recent debate between Plantinga and Dennett. Audio here: http://apologetics315.blogspot.com/2009/02/alvin-plantinga-daniel-dennett-debate.html

I'm a bit late, but I like Alex's answer here: the very same strategy of claiming epistemic humility when it comes to the apparent existence of evil must also apply to the apparent existence of reliable cognitive faculties. But also, whether God is a good hypothesis to explain our cognitive reliability depends upon the liklihood that he exists, not merely the connection between his existence and cognitive reliability.

wombat said...

Noggin - "I just can't see a viable, or even valid test for the existence of the supernatural."

Not really sure I can either but
I suspect it would have to be quite a subtle demonstration and rely on arguments perhaps a bit like those used in Bells theorem to show that no consistent law could account for the results.

At present I am inclined to the idea that anything which can interact with the natural world in any way is itself natural (possibly not material and maybe downright weird like dark energy or whatever the latest astronomical boojum is..). If there were anything supernatural we probably could not experience it at all except in our imaginations.

Steven Carr said...

How does this god guarantee that our cognitive faculties not only generate true beliefs, but also useful true beliefs, granted Plantinga's claim that evolution does not select between useful true beliefs and useful false beliefs?

If I see a tiger running towards me, there are a zillion true beliefs I could generate, but only a few will be useful.

This is what Dennett calls the 'framing' problem.

If no natural machanism can (according to Plantinga) solve such a problem, but the addition of a god can, then the only mechanism is that this god puts the useful true beliefs directly into the believer's head.

Which is a rather shocking consequence of Plantinga's argument....

wombat said...

The way I understood Plantinga's line was not so much that naturalism couldn't provide an explanation merely that the probability was "low or inscrutable".
Of course after a bit of rhetorical mis-direction this more reasonable sounding claim is allowed to grow beyond its original scope.

Alex said...

Anon:

"But also, whether God is a good hypothesis to explain our cognitive reliability depends upon the liklihood that he exists, not merely the connection between his existence and cognitive reliability."

I hadn't thought of it like that! If the probability of God's existence is very low, or the probability of naturalism is very high, then the argument doesn't hold.

anticant said...

Theists postulate the existence of disembodied cognition/intelligence, for which there is no evidence apart from their unsubstantiated assertions.

MrFreeThinker said...

@Get_Education
A good rule of thumb , when reading someone smarted and more respected than you is that if somehow it seems that they are obviously wrong or fallacious , chances say that you ae misunderstanding the argument rather than them being fallacious.
I keep in min that this applies when I read atheistic philosophers too or when I read a scenario like "The God of Eth".

Anyway Plantiga has addresses criticisms there is book book "Naturalism defeated" with essays from several naturalististic philosophers and responses from Plantinga to their counter-arguments.

anticant said...

A lot of these issues would be clarified if Stephen takes up my suggestion of reading and commenting on George Lakoff and Mark Johnson's "Philosophy in the Flesh: the embodied mind and its challenge to Western thought" in his Book Club.

It's obtainable through Amazon.