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Seattle Analytic Philosophy Club Message Board › Alvin Plantinga April 12 in town on April 12 to attack naturalism

Alvin Plantinga April 12 in town on April 12 to attack naturalism

Gene L
user 19640341
Group Organizer
Seattle, WA
Post #: 437
Alvin Plantinga (a very well-known Christian philosopher) will be in town next week to discuss his well-known attack on naturalism (the so-called "evolutionary argument against naturalism"). Thomas Nagel makes a similar argument in his recent book. The arguments are fairly sophisticated.

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Jason
user 3213556
Seattle, WA
Post #: 68

that's an interesting claim... what about this do you find sophisticated?

Gene L
user 19640341
Group Organizer
Seattle, WA
Post #: 438
You'd have to read the detailed exposition of the argument in his book or one of the papers in the professional journals. Plantinga has developed the argument over time to answer criticisms. By sophisticated I mean that the argument takes some time to understand (your initial interpretation based upon cursory reading of it probably isn't what Plantinga is arguing) and Plantinga has addressed the more obvious counters to the argument. The actual argument would be pretty difficult to present to a lay audience, so it might be interesting to see how Plantinga does it.
Jason
user 3213556
Seattle, WA
Post #: 69
You can probably get a sense of how he might present it by taking a look at the outline of a lecture that he gave at an evangelical institution: http://www.calvin.edu/academic/philosophy/virtual_library/articles/plantinga_alvin/an_evolutionary_argument_against_naturalism.pdf­

I think it's a bit surprising how much of a response the philosophical community has given to this argument; if Plantinga is still presenting this and not simply ignoring his critics, there's likely a lot of duct-taped bits added on, but that seems more a matter of complexity than sophistication, at least in the sense of being well informed or absent of naivety.


Jason
user 3213556
Seattle, WA
Post #: 70

He seemed to be presenting the original form of the argument instead of something robust to the criticisms.

Regardless of what he does to bolster the argument, it doesn't actually argue against naturalism anyway.

Gene L
user 19640341
Group Organizer
Seattle, WA
Post #: 439

He seemed to be presenting the original form of the argument instead of something robust to the criticisms.

Regardless of what he does to bolster the argument, it doesn't actually argue against naturalism anyway.


I presume you are talking about Plantinga's presentation, which I didn't attend. But there is no reason he should respond to the philosophical criticisms in a talk to the general public, because of course the general public is not probably not aware of those criticisms to begin with. But I'd be curious to see why you think it doesn't argue against naturalism?
Jason
user 3213556
Seattle, WA
Post #: 71

Many in the general public may not be aware of the criticisms... but he certainly is - the point is intellectual honesty, not whether he fool the uneducated into thinking he made a clever argument.

Here's the argument he presented
p(x) is the probability of x
R is the proposition that our cognitive faculties are rational
(he took this to be a binary quality, though not necessarily requiring infallibility)
N is naturalism
E is evolutionary theory (by which he means biological evolution)
/ is given that (there were other instances which made him appear unfamiliar with formal logic in the talk)

(1) p(R/N&E) is low
(2) One who accepts N&E and also see that (1) is true has a defeater for R
(3) This defeater can't be defeated
(4) One who has a defeter for R has a defeater for any belief she takes to be produced by her cognitive faculties, including N&E.
Therefore,
(5) N&E is self-defeating and can't be rationally accepted.

He didn't try to provide any support for the premises (he does in some talks at religious schools that you can find online and they are not very well argued), except the first where he made an inadequate argument that the probability of a particular belief being true is 50%.

Regardless, even if he could support the premises, the conclusion simply doesn't have anything to say about p(N).


Gene L
user 19640341
Group Organizer
Seattle, WA
Post #: 440

Many in the general public may not be aware of the criticisms... but he certainly is - the point is intellectual honesty, not whether he fool the uneducated into thinking he made a clever argument.

Here's the argument he presented
p(x) is the probability of x
R is the proposition that our cognitive faculties are rational
(he took this to be a binary quality, though not necessarily requiring infallibility)
N is naturalism
E is evolutionary theory (by which he means biological evolution)
/ is given that (there were other instances which made him appear unfamiliar with formal logic in the talk)

(1) p(R/N&E) is low
(2) One who accepts N&E and also see that (1) is true has a defeater for R
(3) This defeater can't be defeated
(4) One who has a defeter for R has a defeater for any belief she takes to be produced by her cognitive faculties, including N&E.
Therefore,
(5) N&E is self-defeating and can't be rationally accepted.

He didn't try to provide any support for the premises (he does in some talks at religious schools that you can find online and they are not very well argued), except the first where he made an inadequate argument that the probability of a particular belief being true is 50%.

Regardless, even if he could support the premises, the conclusion simply doesn't have anything to say about p(N).



I've read Plantinga's book which is overall fairly good and well-argued.

I've posted in the Atheists/Agnostics forum and Drunken philosophy groups asking for some who is wiling to debate me, if I take Plantinga's position. So far I have no takers, but Michael nominated you to defend naturalism.
Michael
Shephard42
Seattle, WA
Post #: 19
I did nominate Jason, partly because I think he has the intellectual chops (and then some) for such a debate, and partly because I know his position on Plantinga isn’t neutral.

I have to agree that Plantinga hasn’t argued against naturalism itself in any of the three lectures I’ve subjected myself to. Perhaps he does so in the book, but in the lectures he restricts himself to simply saying that N&E, if held, leads to a low probability of R, which then defeats all beliefs including N&E.

But I also agree that that argument isn’t as straight-forward as it appears at first glance. There are plenty of examples in currently accepted evolutionary theory of both vestigial traits (in humans and in other species) and adaptively false beliefs (in humans). On the face of it, it does sound absurd to suggest that conscious, believing brains are either somehow vestigial (and thus unconnected with objective reality) or that our perception of reality is largely or entirely composed of false impressions. However, it’s an absurdity that falls well within the wheelhouse of philosophy, and I’m not entirely sure how to disarm it.

It’s certainly true that some of our beliefs do not reflect objective reality – so why not all of them? As long as our behavior (the “movement of our bodies”) is ultimately adaptive, I think Plantinga is right that it doesn’t strictly matter what’s going on in belief land. We think of our beliefs as causing our behavior, but there’s no reason why it’s not *possible* that they either don’t (vestigial or epiphenomenal mind) or that our beliefs are somehow “translated” from a false belief into “true” behavior (i.e. behavior that leads to a successful response to events in the real world).

As an example of the latter, he’s talked about how a belief that tigers are dangerous is not strictly necessary to avoid being eaten by a tiger. It’s relatively easy to come up with any number of completely irrelevant beliefs that would result in running away from the spot you’re standing. Going even deeper than that, there’s no reason why – from an evolutionary perspective – an organism couldn’t evolve to have a conscious mind that “lives” in an entirely virtual world, where every action perfectly mirrors an adaptively useful response in the real world, but isn’t perceived as such. For instance, maybe I’m a creature living in a dense gaseous sea, and I need to rise a little closer to the surface every once in a while in order to facilitate photosynthesis. In my perceived world, I am reaching for my cup of coffee, but in the real world this is translated into the intake of some substance in my environment which can be converted into a chemical generation of buoyant gas in a ballast organ.

I think there’s more than a little solipsism in these thought experiments, but really the question is only “Is there a reason why evolution *wouldn’t* (or couldn’t) select for such false or arbitrary beliefs?”. I’m having a little trouble with that question, myself. I think the strongest response to Plantiga’s overall argument is not to try to answer that question, but instead to ask why the *possibility* of such a scenario should be taken seriously. Listening to his lectures, he hasn’t made a single attempt to describe why such vestigial or virtual minds would be more *likely* to evolve. In the absence of such descriptions, it seems rational to claim that the harsh culling of natural selection would not result in any “evolutionarily expensive” systems unless they were extremely useful, and that the simplest outcome of an evolutionary process would be to have our perceptions align with reality as closely as possible. Furthermore, I think it’s completely appropriate to argue that such simplicity can be defended not only by an Occam’s razor mentality, but is in fact a core hypothesis of evolutionary theory.

Anyway, that’s my take on it. I just realized that you might be holding back a little here, Gene, in the hopes of organizing an IRL debate, but I’ve been thinking about this for a few days, and figured I’d add my thoughts. Also, I don’t think I’d make a good real-time opponent for you on this subject, and I’d like to see someone with a more academic background in the inaugural debate.
Jon C.
JonCohen
Mercer Island, WA
Post #: 157
I didn't attend the lecture, but it sound like it was similar to this lecture given in 2006: http://www.youtube.co...­ There are more Plantiga lectures at http://www.youtube.co...­ I am not familiar with any changes he made since then to refine his argument.

Plantiga does make some interesting points, but sadly he also uses some logical fallacies also.

His argument is that natural selection operates only on behavior producing faculties and that belief producing faculties are epiphenomal with regard to natural selection. If one concludes that our belief producing faculties are not reliable, then we cannot trust them to produce correct beliefs about natural or evolution. He attributes this line of reasoning to Darwin.

One interesting point is that if a naturalist claims that evolution does produce correct beliefs, then the naturalist has to explain the widespread belief in religion. The naturalist might claim that society is evolving towards atheism, but my opinion is that trend is a relatively short term event that is related to a widespread belief in the idea that classical mechanics can explain our world. I believe that when there is wider understanding that classical mechanics does not actually explain very much of what we observe in everyday life, then naturalism will lose its appeal.

However, Plantinga does make some mistakes. One is that he assumes that the probabilities that different beliefs are true is independent. That is part of his reason for believing that the probability of having correct beliefs is low, because there are so many of them. Actually, if evolution does lead to a mechanism that produces generally true beliefs, then the resulting probability that most beliefs are true would be very high. So the probabilities of the truth of various beliefs are actually highly correlated.

Another mistake is related to the claim he makes that there are four possibile cases of relations between belief and behavior, and that in each of these cases the P(R|N&E) is low. Its hard to really understand his explanation of the different cases, so its hard to verify that the cases are exhaustive. The big problem is that his responses to the questions at the end was to dismiss objections by citing one or another of his cases at will to say that in that case the stated objection was not valid. That of course is not a legitimate form of argument.

He cited the example of the tiger, which is apparently based in several respects on the behavior of his cat. But evolution would start off with simpler organisms in scenarios where there are fewer levels of abstraction, so the difference between behavior and belief would be minimal, because the belief system is so minimal. Then more complex behaviors and belief systems would evolve. Without doing the math, it seems implausible that evolution would allow those to diverge in any meaningful degree as the systems became more complex.
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