Wednesday, September 14, 2005

A debate on Plantinga's Evolutionary Argument Against Naturalism on iidb

This is a debate on the Internet Infidels discussion forum on Plantinga's anti-naturalism argument.

24 comments:

Steven Carr said...

http://www.bede.org.uk/2004_11_01_bedesblog_archive.html

Here , Plantinga is quoted as saying 'We do not evolve a fear of snakes or a love of sugar unless there are real snakes and real sugar to set it off.'

So evolution does produce true beliefs after all....

Steve T said...

Thanks, Victor. I'm writing a paper on the EAAN for the fall, and this thread will be helpful.

Anonymous said...

Until now I have never read Plantinga's argument. I find it bothersome. I consider myself an atheist who leads more towards agnosticism...
I am reading the debate over at IIDB and I am frustrated by some of the responses to the pro-Plantinga poster. Non of their responses seem very effective. Please someone post a link to a decent refutation of Plantinga's argument.

I'll be the 1st to admit (and not ashamed of it) I am an atheist for emotional reasons primarily. I don't want to get into the discussion of it, but I don't want theism to be correct.

Steven Carr, I've read some of your posts before and you seem intelligent, but your argument does very little for me. I don't see how it counters what Plantinga is saying. Could either you devise or point me to something that successfully refutes what Plantinga is saying?

Mike D said...

I would like to try to help Anonymous. This is strange because I am a theist. I will have to argue opposite my beliefs.

I am asking whether survival actions function best only if they are based on true beliefs. If it is true that false beliefs produce survival actions just as well as true beliefs, then I think you have a hole in the argument. This, in fact, is the state of our world. Millions of people are adequately surviving while holding to false and even harmful beliefs. Some of the false beliefs have no application to their survival issue. Other false beliefs are as good as true beliefs for their survival. Some false beliefs are better than true beliefs to motivate survival behavior. As another posted, we may have false beliefs that would be harmful or fatal if we acted on them but for unknown reasons choose to behave opposite our beliefs (survival of the hypocrits).

The soft point may be whether there is a clear cause an effect relationship between belief and behavior. And whether only true beliefs result in survival behavior.

But I hope I am wrong about this.

Steven Carr said...

How can Plantinga's argument be refuted when he doesn't make one?

What is his argument?

Plantinga argues that if natural selection is true, then people who believe in natural selection are likely to have false beliefs about natural selection.

But if natural selection is false, people who believe in natural selection are likely to have true beliefs about natural selection.

This is a rather counter-intuitive result.

You might be able to explain Plantinga's argument a little better than I can.

To me it runs :-
1) False beliefs are sometimes as useful for survival as true beliefs
2) Belief in naturalism has evolved
3) Therefore, belief in naturalism may be false
4) Therefore, belief in naturalism is false

If he is doing no more than claim that it is irrational to believe naturalism when naturalism may be false, then that is an absurd position.

If it is only rational to believe in something when you have utter certainty that it is true, then theists are going to be in big trouble.

A Scoundrel said...

Carr,

Plantinga doesn't so much argue that a belief in natural selection is irrational, but that a belief that natural selction is a COMPLETE account of our origins (in particular, the origin of our cognitive equipment) is irrational.

But since naturalists do hold that the evolutionary account of origins is essentially correct (evolution is, for them, the only game in town) then they, in their capacity as evolutionists, fall under the argument.

So, obviously, if it is false that a naturalistic account of our origins is true, then, ofc, we shouldnt believe it - or expand on it, rustle up a little teleology from theism's big barns, say.

But that is beside the point since Plantinga doesnt argue for the falsity of the naturalistic account of our origins but rather for their irrationality.

Sticking close to how you see Plantinga's argument, i would say that it runs more like:

1) For the production of survival enabling behaviour B, there is a set of beliefs, X, that contains all those which can cause B. (Only one belief in this set needs to obtain in a subject for B to obtain in that same subject.)
2) The set X can be divided into 2 other sets: a set of false beliefs, F, and a set of true beliefs, T.
3) F is larger than T.
4) B has obtained, (after all, we are here.)
5) The decision as to which belief in X is used for B is random, it is not guided.
6) Since set F is larger, more likely it came from the set F rather than the set T.
Therefore,
7) More likely our beliefs are false rather than true.

Of cour se, the theist can quite contentedly deny 5) since he/she wouldnt believe that their cognitive faculties were assembled without guidance - they were guided by the all-seeing hand of God.

So if you take a belief in evolutionary naturalism, EN, then you lo ok at the conclusion drawn from EN ("7)") and you, accordingly, should conlclude that EN is more likely false than true. Thus is a belief in EN irrational.

I would've posted this on infidels but decent conversation and discussion is impossible there - it's the seedy corner among the set (C) of all cyberforums...

Ahab said...

Under evolutionary theory, our cognitive abilites are not the result of purely random processes. The random elements are, so to speak, filtered through natural selection.
And as was pointed out in the discussion over at IIDB, evolutionary processes don't work on individual beliefs so much as on the belief forming mechanism (the brain).

In any case science has done a pretty good job documenting just how frail our cognitivie abilities can be. That is one reason why we've had to develop disciplines like logic and the empirical sciences in order to help us come to a more accurate understading of the world.

I would think (5) would be a problem for the theist because there is no way to know if this God or demon or whatever is going to assemble a well-working belief forming mechanism.

Steven Carr said...

And Plantinga's argument is dead wrong on such a vast number of points that it is really hard to know where to start.

There are more false beliefs than true beliefs. That is true, but there are a lot of ways to die, and most of the false beliefs will lead to death.

And beliefs are not hereditary, so they did not evolve.


And Plantinga runs into huge trouble because under theism, his cognitive faculties are under constant attack by supernatural entities , highly motivated to deceive him and capable of doing so.

Of course, somebody who is too scared to defend Plantinga on a sceptical forum is probably too scared to admit that he believes in demons that attack his reasoning.

Steven Carr said...

And we musn't forget that Plantinga argues vehemently that the minds of people who believe in naturalism are minds formed by God to discern truth.....

Ahab said...

Good point, Steven. I hadn't thought of that one!!

Steven Carr said...

Plantinga's defense to the Logical Problem of Evil is that God might not be able to create beings with free will that never choose evil.

Plantinga himself told me that God can and has created beings with free will that never choose evil.

So while Plantinga has shown that it is logically consistent to say there is a defense to the logical problem of evil, by Plantinga's own methods, it is *irrational* to believe that there is a defense - because the defense rests upon something which is false.

Plantinga's argument against naturalism depends upon separating logical consistency and rationality.

So he might be able to find a logically consistent defense against the logical problem of evil, but because his defense is factually false, it is irrational.

HV said...

For an interesting critique of evolutionary arguments applied to the theory of mind and belief/behavior and intentionality see Hilary Putnam's "Renewing Philosophy", Chapter 2. One point he makes is evolutionary explanations depend on counterfactuals, and the theory of counterfactuals is problematic. I haven't figured out how this applies to Plantinga.

Dennis Monokroussos said...

Plantinga doesn't claim that the naturalist's cognitive faculties aren't working properly. What he claims is that believing naturalism turns out to be a defeater for other beliefs - including naturalism itself.

A parallel case is belief that there we're brains in vats, or that the Cartesian evil deceiver exists and is in charge of our epistemic lives. As long as we hold those beliefs, we are thereby given a reason to doubt all our beliefs. And this is true even if God exists. The solution in all three cases is to chuck the global doubt-inducing belief: naturalism, that we're brains in vats, and that there's a Cartesian evil deceiver in charge of our epistemic lives.

On beliefs with survival value: Plantinga's claim is that false beliefs could do the trick as well as true beliefs, so that N&E doesn't guarantee that our cognitive faculties are functioning properly. Indeed, there are plenty of naturalists who think this - all qualia eliminativists and epiphenomenalists, for example.

There seems a lot of confusion about how the argument works, so I'd suggest that interested parties read Naturalism Defeated?, ed. by James Beilby (Cornell UP, 2002). After a brief introduction by Plantinga, 12 heavyweight critics go at the argument, and Plantinga offers responses in the final chapter.

Steven Carr said...

'On beliefs with survival value: Plantinga's claim is that false beliefs could do the trick as well as true beliefs, so that N&E doesn't guarantee that our cognitive faculties are functioning properly.'


You mean people who believe in naturalism are irrational if they believe the sky is blue?

Because a false belief that the sky is blue is just as valuable to survival as a true belief that the sky is blue?

Utter nonsense.

The fact that we have a reason to doubt our beliefs does not in itself make a single one of our beliefs false.

Not a single one. All it means is that we should be open to the possibility that they are wrong.

Plantinga's argument is a huge ad hominen.

X believes some things that are false. Therefore, all things that X believes may be false. This is a huge fallacy.

And theists *do* believe in the supernatural , which means they cannot rule out the fact that their beliefs have been caused by evil demons, including their belief that they should not believe in evil demons.



So theists are in a worse position than non-theists.

And don't forget that we can use Plantinga's arguments to show that it is rational to believe that we only have one leg.

http://dangerousidea.blogspot.com/2005/08/carr-on-plantinga.html

As a Plantinga defender wrote to me Start quote '1] Everybody except me has one leg.

[3] My memory is that almost everybody has two legs.

You then raised the issue as to whether [1] and [3] are consistent.

I think it's obvious that they are.'

end quote.

So , according to Plantinga's logic, theists are rational if they believe people have one leg, but naturalists are irrational if they believe the sky is blue.

Perhaps now you understand the fact that Plantinga's argument was met with such laughter on IIDB.

Dennis Monokroussos said...

Straw men are easy to laugh at! That's why it's a good idea to take a look at the work I mentioned. If you'll find that philosophers who are (a) universally acclaimed practitioners in their field, (b) are almost all naturalists, and yet (c) don't offer the critiques you're mentioning, it might offer grounds for suspicion that something has gone awry in your interpretation, or in the interpretation of those from whom you're learning the argument.

So I'll try a second time, and then reply to your parody argument.

Plantinga isn't arguing (1) we have reason to doubt our beliefs, therefore (2) our beliefs are false. That would be silly, and even if a philosopher of Plantinga's stature could make such an error in a careless moment, it's beyond reason that he could maintain such a blunder for more than a decade.

So, for starters, Plantinga's ultimate conclusion is that believing naturalism is irrational. As I wrote in my previous comment, the naturalist apprised of and convinced by Plantinga's argument has a defeater for all her beliefs, including naturalism itself. To have a defeater for a belief is to have some bit of evidence that makes holding that belief less rational. There's no mention of truth here whatsoever.

Next, it's not the mere possibility that our beliefs could be wrong, if naturalism is true, that gives us a defeater. It's much stronger: if naturalism is true, then, following an evolutionary story, belief-forming faculties formed by such processes are unlikely to produce a predominance of true beliefs relative to false ones; or, more modestly, we have no clue as to what the likelihood is of reliable cognitive faculties' being formed in that way.

Plantinga's overall argument goes like this (approximately):

(3) If naturalism is true, then the probability that our cognitive faculties are reliable (i.e. produce a preponderance of true beliefs to false ones) is low or inscrutable (~R).

(4) If ~R, then we have an epistemic defeater for beliefs formed by our cognitive faculties.

(5) Our belief in naturalism has been formed by our cognitive faculties.

(6) Therefore, if ~R, we have an epistemic defeater for naturalism.

(7) Naturalism is true (naturalist's premise).

(8) Therefore, ~R.

(9) Therefore, we have an epistemic defeater for our belief in naturalism.

(10) This epistemic defeater cannot itself be defeated, because any defeater-defeater is itself defeated by ~R.

(11) Therefore, we have an undefeated epistemic defeater for our belief in naturalism.

(12) But, since we know we have knowledge of various truths, then since believing in naturalism would imply that we don't, we ought to reject naturalism.

Plantinga argues that bare theism is in the same boat as naturalism, as we would have no idea of the likelihood that some random deity would have bothered to give us cognitively reliable faculties. Christian theism, however, escapes, as there the likelihood of R is quite high, given the Judeo-Christian understanding of God's purposes for human beings.

Don't like his argument? That's fine, but work a bit to make sure you get it right before swinging the axe.

Steven Carr said...

So Plantinga offers no evidence that naturalism is false, yet claims that it is irrational to believe in naturalism?

Plantinga even agrees (according to you) that the fact that we have some false beliefs *has no bearing* on the truth of naturalism.

I quote you 'To have a defeater for a belief is to have some bit of evidence that makes holding that belief less rational. There's no mention of truth here whatsoever.'

So why should I accept an argument that has no bearing on the truth of what I believe.





Any book on science will tell you that common sense beliefs about how the world work are very often wrong. This is no grounds whatsoever for disbelieving science or naturalism. It is a joke to think that Quantum Chromodynamics is a belief formed by natural selection.



And his ludicrous claim that he can ignore the possibility that his senses are being attacked by demons, because that is not part of his belief set is silly.

If a doctor tells me that I have cancer, and tells me that people with this cancer might die in six months, I cannot claim that there is no defeater for my belief that I will certainly not die in 6 months, because I choose not to believe the doctors claim.

I would have to prove the doctors claim false.

Similarly, Plantinga's 'get out of epistemic jail free' card, that his beliefs do not include that of a supernatural demon fails, until he can prove that no supernatural demon exists that has corrupted his senses into thinking that Christian theism is true.

I notice that you haven't even bothered to defend the implication that Plantinga thinks it is irrational for naturalists to believe the sky is blue.

I shall give the argument and you can tell me why it is wrong

3) If naturalism is true, then the probability that our cognitive faculties are reliable (i.e. produce a preponderance of true beliefs to false ones) is low or inscrutable (~R).

(4) If ~R, then we have an epistemic defeater for beliefs formed by our cognitive faculties.

(5) Our belief in the blueness of the sky has been formed by our cognitive faculties.

(6) Therefore, if ~R, we have an epistemic defeater for the blueness of the sky.

(7) Naturalism is true (naturalist's premise).

(8) Therefore, ~R.

(9) Therefore, we have an epistemic defeater for our belief in the blueness of the sky.

Steven Carr said...

You wrote 'As I wrote in my previous comment, the naturalist apprised of and convinced by Plantinga's argument has a defeater for all her beliefs, including naturalism itself. '

Including , of course, the belief that the sky is blue.

So why is it rational for naturalists to believe the sky is blue, apart from the obvious fact that we can see a blue sky?

Dennis Monokroussos said...

The naturalist does have a defeater for her belief that the sky is blue, just as she would if she took seriously the worry that she was in the Matrix. (We wouldn't have a defeater for the claim that what we took to be the sky appeared blue, but that's different.)

Note: her belief that she might well be in the Matrix doesn't prove that the sky isn't blue. She would still have the same evidence anyone else has for the truth of that proposition. Her problem is that she has a reason to doubt the relevance of that evidence.

While the structure of the problem at this point is similar, how the Matrix argument and Plantinga's EAAN reach this point is different. So it would be wrong to claim Plantinga argues from the bare possibility of a skeptical outcome to the conclusion that P(R/N&E) is low or inscrutable.

Steven Carr said...

You mean it really is irrational for naturalists to believe that the sky is blue?

Because humans are fallible beings who often make mistakes, we have a defeater for 'The sky is blue'?

I looked at some reviews of the book you mentioned. It was intriguing how Plantinga switched from the obviously false claim that true beliefs have no survival advantage over false beliefs, to the claim that naturalists cannot explain how true beliefs cause survival behaviours.

Naturalists don't need to explain that to refute Plantinga's argument which depends upon claiming that natural selection does not favour true beliefs over false beliefs.

As for Plantinga's claim that the probability is low, I refer you to where Bede quotes him as saying 'We do not evolve a fear of snakes or a love of sugar unless there are real snakes and real sugar to set it off.'

Of course Plantinga was talking to theists who believe in natural selection, so he is not going to tell them that they have a defeater for their belief in theism.

And Plantinga simply cannot claim that he knows that God would never allow the evil of us having cognitive faculties that were not reliable, or that God would never allow evil demons to deceiev us.

That would be an evil and Plantinga maintains that we cannot rule out such an evil.

' The fact of the matter is that we do not and cannot know what is the quantitative sum of evil in the world....... The existence of evil may present problems for theists, that is, religious, emotional, pastoral, and other such problems, but Plantinga claims evil does not present an epistemic problem for believing in God. Humans do not have access to the kind of knowledge that is needed to justify that the quantity of evil makes belief in God unlikely.'

'If God has reasons for permitting these evils to exist, what makes anyone think he would tell those who believe in him what they are? Maybe God's reasons are beyond human's capacity to be known.'


http://apologetics.johndepoe.com/evidentialevil.html

Of course, Plantinga is nothing if not inconsistent.

His epistemic certainty fades whenever convenient.

Plantinga's argument seems to be that we can't claim that an all-loving God would never have allowed Japanese soldiers to bayonet Chinese babies during WWII.

All we can know is that God made sure the babies faculties were very reliable , so that they truly experienced agony, when being bayonetted to death.

Dennis Monokroussos said...

Okay, it's clear that this is a waste of my time, but I was intrigued by your reference to a direct quote from Plantinga which, at least on the face of it, seems inconsistent with what he's generally arguing.

So I scrolled up, found the url, did a search for Plantinga, and found that:

(A) The context was a spoken lecture, not a print source (misstatements and inaccuracies in oral contexts are obviously much more common).

(B) Bede didn't attend the lecture, but based his comments on a handout and what he picked up from those who attended. There's no indication in Bede's comments that the statement in question came from the handout rather than the interpretation of an audience member.

(C) Relatedly, what you've claimed to be a Plantinga quote (in the first comment on this thread, as well as in the previous comment, to which this is a response) is in fact not offered as a quotation by Bede.

(D) It's not clear that the alleged quote is even part of Plantinga's claim, though it may well be. (I'm not denying it; I'm just not 100% sure.)

(E) If we pretend it's of significance to the EAAN, it turns out that it still doesn't help the naturalist responder, because if Plantinga's argument is correct, saying that a fear of snakes and love of sugar require real snakes and real sugar doesn't tell us that we know that we evolved or that snakes and sugar exist.

(F) Most fundamentally, it has absolutely nothing to do with the EAAN. So what's the point?

To answer your initial question, I could just refer you to Dawkins on the "argument" from personal incredulity, but in case you're sincere, yes, the naturalist that accepts that P(R/N&E&C) is low or inscrutable has a defeater for all her beliefs as long as she holds to N&E (which collapses to N). This shouldn't cause any more gaping than the realization that someone who (a) thought the likelihood of no Cartesian evil deceiver low or inscrutable and (b) understood the implications that belief had on his epistemic life would have a defeater for his belief that the sky is blue.

So try the Beilby volume, and the Howard-Snyder collection on the Evidential Problem of Evil if you're interested in principled argumentation on the subject.

Steven Carr said...

Again, it is gibberish to claim that if our cognitive faculties have developed through natural selection, we cannot trust our beliefs.

It makes no more sense than claiming that because natural selection had not enabled us to lift weights of one ton, then we cannot rely on our cranes to lift large weights.

And on the Christian hypothesis, the chance of God deluding people is very high (see 2 Thess 2:11
For this reason God sends them a powerful delusion so that they will believe the lie and so that all will be condemned who have not believed the truth but have delighted in wickedness.'

Christians certainly believe in evil demons that deceive our cognitive faculties.

But you are correct. Trying to defend Plantinga's argument is a waste of time.

A Scoundrel said...

Trying to defend Plantinga's argument is only a waste of time if it's conclusion is false, and naturalism isn't an irrational belief, but don't you think that's slightly question begging?

To me your responses simply illustrate a lack of understanding, and if that is the case it is an affliction which an easy to understand explanation should suffice to remove; so i'll give it one last shot:

Imagine that, on some planet in Alpha Centauri, naturalistic evolution is occuring (however much this might stretch the imagination.) The life forms that are emerging are deveping sight, say. Imagine further that on this planet the sky is a murky shade of green.

Now evolution, as I am sure we are all agreed, produces the increasingly complex lifeforms that it does according to (among others) the following mechanism: beneficial mutations (those that increase survival potential) are, by and large, kept in the gene pool, while the not so hot mutations are weeded out, and the species that possess them die.

But the mutations are RANDOM are they not? There is no God or anyone else who decides what animal gets what genetic mutation at what time, is there? Granted, if a dog is born with one leg, it will most likely die, and there is no chance of gene-passing there. Nature, to speak figuratively, rolls dice to see what genetic mutation turns up; and when she, PURELY BY CHANCE hits on one that is beneficial, that animal breeds more (or whatever) and the gene sticks in the pool and, voila, we have natural selection.

So there is nothing that guides nature's mutations, merely the results of those mutations (the improved or lessened survial capacity of the animal.) BAD GENES (to ram the point home) ARE WEEDED OUT ON THE BASIS OF SURVIVAL CAPACITY.

Now, to return to Alpha Centauri, I don't know how many colours there are considerd to be, (colours, that is, qua primitive, simple entities,) but let us suppose that there are twenty. It follows from this that at least 19/20 beliefs about the basic coulor of the sky are wrong, and that 1/20 (the sky is green) is true.

Consequently, when nature rolls her dice over there, what sort of cognitive equipment will she produce? Regarding the equipment which happens to produce beliefs about the sky there are (simplifying) 20 basic possibilities, and only 1 of these produces true beliefs (that equipment which produces the belief "the sky is green".) Now given, as we agreed before, that mutations are RANDOM, which cognitive equipment is more likely to be picked? There is a 19/20 chance that it is equipment which produces a false belief.

But, I hear you cry, won't those poor creature who have the equipment that produces false beliefs about the colour sky die out?

But why should they? How on earth can a belief in the colour of the sky aid ones survival potential? Those who believe that the sky is pink will get along just as fine as those who believe it is orange.

And, of course, since a belief or disbelief in naturalism, or in any abstract, metaphysical topic, is utterly irrelevant to ones survival value, we have, again, no such reason to think that beliefs that we hold in such areas (ex nauralistic hypothesi) are true - most likely they are false, and so the naturalist has a defeater for all his beliefs.

I hope this sheds some light.

P.S. You're dead right when you say I'm scared to post on infidels. Im scared that decent, logical, coherant discussion will be left by the wayside; and that ad hominem, sniping and people posting pictures of Darth Vader with the caption "the irony is strong with this one" will take their place. Now surely none of us want that? Do we?fi

Steven Carr said...

I see.

So if I believe that natural selection has a low probability of me having reliable eyesight with an accurate view of the world, then the fact that natural selection has given me unreliable eyes means that I have no grounds for my belief that wearing glasses will improve my eyesight?

Steven Carr said...

'And, of course, since a belief or disbelief in naturalism, or in any abstract, metaphysical topic, is utterly irrelevant to ones survival value, we have, again, no such reason to think that beliefs that we hold in such areas (ex nauralistic hypothesi) are true - most likely they are false, and so the naturalist has a defeater for all his beliefs.'

I just love the idea that naturalists have a defeater for the belief that 8 times 7 is 56.

While , by using Plantinga-logic, theists on this blog have argued that it is logically consistent for theists to believe that people have only one leg.