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Fri Dec 16, 2011, 04:07 PM

Plantinga's evolutionary argument against naturalism

Last edited Sat Dec 17, 2011, 12:27 AM - Edit history (1)

I just finished listening to this (a debate between Alvin Plantinga and Stephen Law on Premier Radio):

...which goes on for about an hour.

Or perhaps I should say drags on for about an hour. I didn't feel like either guy put their best case forward. Perhaps either or both thought that their better arguments were too technical, and they were floundering a bit because they found it difficult to simplify what they wanted to say for a general audience.

For something a bit more concise than the YouTube version, here's the Wikipedia article on the subject: http://en.wikipedia.org/wiki/Evolutionary_argument_against_naturalism

My own summation would be this: Since naturalistic evolution (NE) only selects for survival value, not for "true belief", there's nothing that would require beliefs to be true, as long as outward behavior has a survival benefit. For example you might run every time you see a bear because you believe it's fun to race against bears, not because you're afraid of being killed, but as long as you run, that outward behavior is all NE can select for. NE can't select for or against the internal state of mind (Plantinga calls this "content" ) that goes along with the neurophysiological apparatus that causes you to run.

Plantinga claims that this lack of a necessary correlation between outward behavior and internal thoughts makes those internal thoughts, within the kind of brain NE would produce, unreliable. If individual thoughts are unreliable, complex chains of thoughts must be all the more so unreliable (a conclusion based on ten different thoughts, each with only a 50% chance of being correct, has less than a 0.1% chance of being correct). Since a belief in naturalism is itself a complex conclusion, a person who believes in naturalism should conclude that his own mental faculties are so unreliable that his belief in naturalism itself is highly unreliable.

So (by my interpretation of Plantinga), if you want to trust your own thoughts, you're better off trusting that God designed your mind.

As I see it, this is total bullshit. Interesting and clever bullshit, but bullshit nevertheless.

Anything that you can reasonably call "intelligence" has got to be able to handle complex multi-step processes with a reasonably high degree of reliability. If you're going to allow, for sake of argument, that intelligence can come about through natural evolution (Plantinga does allow for that, even if only because he thinks it leads to a contradiction, but he still does allow for it as an initial premise), then what kind of intelligence would it be, and what kind of survuval advantage could it confer, if was a highly unreliable intelligence?

Could intelligence be highly reliable for matters of survival, but not for philosophical matters? I suppose so, but I see no strong case for assuming that. Clearly one aspect of human intelligence which has aided our survival -- even more, allowed us to flourish -- is the evolution of complex language. It would make perfect sense that a naturally-evolved language capability relies on a naturally-evolved system for complex abstract symbolic reasoning.

It would make very little sense, however, and it would be highly inefficient, for an evolved abstract symbolic processing system to carry the burden of the extra baggage of a lot of extraneous, perhaps even contradictory, "content" (in Plantinga's sense of that word), where you could succesfully negotiate all of the symbolic processing necessary to recognize a bear, visually parse a complex landscape and quickly determine an efficient escape route through that landscape, avoid crashing into trees and tripping over rocks, and all that while performing an extra layer of extraneous symbolic processing which involves seeing a bear as a playmate and seeing running away as a game.

What would be even more unlikely would be for such extraneous and mismatched "content" to be shared among multiple humans. It would cause a great deal of communication difficulty (and potentially life-threatening confusion) if unrelated and unreliable "content" got mixed in with our vocalizations.

Would it even mean anything coherent to suppose that I might run from a bear because I think I'm playing a silly game, but that when I explain to a fellow human being why I'm running from the bear the words, "Because I don't want to get eaten!" come out of my mouth? To imagine "content" that never manifests in any noticeable outward manner is to imagine something so abstract that it might as well be invisible pink unicorns.

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Response to Silent3 (Original post)

Fri Dec 16, 2011, 06:53 PM

1. When you talk about survival ...


Last edited Fri Dec 16, 2011, 08:37 PM - Edit history (1)

are you imagining survival under some idealized living arrangements?

"Could intelligence be highly reliable for matters of survival, but not for philosophical matters? I suppose so, but I see no strong case for assuming that."

If the Bible deals with, among other things, philosophical matters, and if the Bible is a product of human intelligence, and if human intelligence is highly reliable for philosophical matters, then ...?

I anticipate that some people will say that cultural conditions prevented human intelligence from being reliable on philosophical matters while the Bible was being written, while Christianity was the official religion of the Roman Empire, and during the medieval period.

How do we know that cultural conditions are now adequate to allow human intelligence to be reliable for philosophical matters?

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Response to Silent3 (Original post)

Fri Dec 16, 2011, 06:59 PM

2. Without saying anything about Plantinga's ideas, I think is is undeniable that:

... naturalistic evolution (NE) only selects for survival value, not for "true belief" ...

I think it would be amazing if our intelligence tended to generate "true beliefs". Our inability to conceptualize the data from studies at the quantum level may well be an indication of the limitations of our ability to comprehend reality.

There is strong evidence that (non-human) apes cannot process grammar. They lack the requisite brain structures. I believe that human intelligence is, similarly, incapable of grasping "events" at the quantum level. Do you disagree? If so, why?

You call Plantinga's ideas bullshit. Do you think there is any reason to believe that any of our ideas about the ultimate nature of reality are any less bullshit? If so, why?

Note: I didn't listen to the audio.

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Response to Jim__ (Reply #2)

Fri Dec 16, 2011, 08:32 PM

4. Plantinga doesn't argue that "true belief" is unlikely or impossible...

...only that, if there's any hope of such a thing, naturalistic evolution is unlikely to be compatible with the capability for "true belief" -- which I'd define in this context as a mental state corresponding with actual conditions in the real world.

If you entertain radical doubt about the human capacity to ever generate "true beliefs", however human mental faculties came to be, then you have to give up going any further with examining that argument at all, whether from a pro-naturalism or anti-naturalism standpoint, because with that kind of doubt as a starting premise you simply can't trust your mind to go any further.

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Response to Silent3 (Reply #4)

Sat Dec 17, 2011, 09:46 AM

7. You can trust your mind to get certain things right, things pertaining to survival.

As an aside, our minds evolved to survive in a hunter-gatherer world. I'm not sure how attuned they are to survival in a world of nuclear weapons. But, that's a different issue.

You define "true belief" as a mental state corresponding with actual conditions in the real world. Then you say that if I doubt that the human mind can actually generate such a state, then I can't trust my mind to go any further. I disagree.

Using your metaphor of mental states, I don't think that we can generate a mental state that corresponds with conditions in the real world. There are more components and more possible relationships between those components than there are potential human mental states. However, that doesn't mean we can't learn to generate mental states that are closer to actual conditions in the real world than the mental states that we are currently able to generate. My belief is that we can go farther; we just can't get all the way there.

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Response to Jim__ (Reply #7)

Sat Dec 17, 2011, 12:03 PM

8. I'm trying to stick to the terms set up by Plantinga

My example with a bear is very much like Plantinga's own example with a tiger. He was casting doubt even on the things you might believe even in basic life-or-death survival situations. Plantinga himself was not making a survival vs. non-survival belief distinction.

If you want to have a separate argument about whether there are different categories of thought in which humans are competent, and others which they are not... well, that's certainly possible. Even likely. But there's no "gotcha" there for someone who favors naturalistic evolution, no compelling reason to assume thoughts about about naturalism are among those which are beyond evolutionarily-generated mental competence.

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Response to Silent3 (Reply #8)

Sat Dec 17, 2011, 06:00 PM

9. Why are you talking about human competence?


Competence normally means ability to function within a system that includes other people and the natural world.

If you suspect that beliefs you have been taught are false, then what do you do? You might be right in your suspicion, but you might yourself have false beliefs that you acquired without paying much attention to them and without realizing that there could be anything controversial about them.

Furthermore, a conflict of beliefs might eventually help the community when the community revises its beliefs, but at least in the short term and often in the long term, if a minority group (possibly only one person) proposes an alternative belief in conflict with prevailing beliefs, then the minority group usually gains nothing. Almost all of human evolution took place before human beings had written language, so using a pen name (such as Mark Twain, Doctor Esperanto, or George Orwell) wasn't an option.

Isn't it unusual for one person in some community to pass on his or her genes, and for all the other members of the community to fail to pass on their genes because they had some particular false belief? If most of a community has a false belief, then I'm wondering how recent the belief is. The human beings who are members of the community descended without break from a long line stretching all the way back to single-celled organisms. No past false belief prevented their ancestors from reproducing. Is the false belief something very new, or did conditions in the world suddenly change to make a belief that was true no longer true?

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Response to Boojatta (Reply #9)

Sat Dec 17, 2011, 06:31 PM

10. Ask Plantinga.

It's his argument, not mine.

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Response to Silent3 (Original post)

Fri Dec 16, 2011, 08:10 PM

3. I think he fails to understand the processes involved connecting mind and body...


people with no fear, for example, wouldn't run from the bear at all, or if they ran from it for "fun"thrill seekers I guess), they wouldn't put nearly as much energy into it as someone who was genuinely afraid of the bear. Adrenaline kicks in much faster, response times increase exponentially, etc. when we are under a great deal of stress. Hence, the person afraid of the bear and having a proper fight or flight response is more likely to reproduce versus the person who doesn't have this response.

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Response to Silent3 (Original post)

Fri Dec 16, 2011, 11:12 PM

5. I don't have the patience to watch that video for over an hour. Looking over the Wikipedia summary,

my reaction is that the whole proposed debate hinges somehow on the proposition that some ideas are "true" and on the notion that we can meaningfully distinguish between thinking that corresponds to "true" ideas and thinking that is merely useful, whether the underlying ideas are "true" or not

But such a distinction cannot be made in scientific work: science does not aim at ideas that are "true" -- rather it aims at ideas that are predictively useful. It is, for example, entirely pointless to argue whether it is "true" that planets orbit the sun along ellipses with the sun at one focus: the scientific test, of this intellectual picture, is simply that it is predictively useful

Now, a naturalist might indeed sometimes use the word "true" but then means "predictively useful." But then to argue with naturalists, Plantinga proposes to use "true" in a manner that does not correspond to the manner by which naturalists use the word. This is guaranteed to lead to an entirely inconclusive discussion

"True" is actually a very tricky word, with many pitfalls. In mathematics, for example, is "true" synonymous with "provable"? If it is not, you will probably encounter significant Platonistic baggage; if it is, then most of modern mathematics may evaporate, leaving us a bizarre and incredibly difficult logical landscape

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Response to struggle4progress (Reply #5)

Sat Dec 17, 2011, 12:53 AM

6. Do turkeys have a science of human behavior?


It is entirely pointless to argue whether it is "true" that people give food to turkeys out of benevolence. The only relevant question is whether or not the theory that benevolence motivates human beings to feed turkeys is predictively useful. Indeed, it is predictively useful. However, it fails to be predictively useful when the turkey is slaughtered. At that moment, it's too late for the turkey to start thinking about the possibility that there were things worth knowing that went beyond mere usefulness in making predictions.

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Response to struggle4progress (Reply #5)

Sat Dec 17, 2011, 09:32 PM

11. excellent

as societies, we have decided that certain measurements mean certain things. if we can predict something will happen using those measurements, and if others can reproduce our results, this is a useful.

what the materialist world works with are measurements.

no doubt we are "unreliable narrators" of this world - the idea that god makes more sense when imagined by that same unreliable mind makes no sense either - rather than present an argument for god, it's an argument for nothing - because they're the same if we are unreliable narrators who can make no sense of the world.

but we do make sense of the world and reach agreements via measurements that are shared... i.e. the scientific method.

since those agreements are not reached by the working of some magical force, they can be corrected when better measurements are understood.

I didn't bother to watch the show either - the wiki summary was enough to make me say... wha? but maybe the guy has some other argument for a belief in a mind that makes things up all the time to explain the world.

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