# Evolutionary argument against naturalism **URL:** \ **Category:** Great Debates\ **Created:** [March 15, 2007, 8:26pm UTC](https://boards.straightdope.com/t/evolutionary-argument-against-naturalism/396082 "2007-03-15T20:26:33Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Meatros](https://avatars.discourse-cdn.com/v4/letter/m/b4bc9f/32.png) [@Meatros](https://boards.straightdope.com/u/Meatros)\ **Post date:** [March 15, 2007, 8:26pm UTC](https://boards.straightdope.com/t/evolutionary-argument-against-naturalism/396082/1 "2007-03-15T20:26:33Z")
I did a search and I couldn’t find any threads on Alvin Plantinga’s argument against naturalism. What are people’s thoughts on it? Personally I find it very unconvincing. I also find it to be obviously unconvincing. Here is Alvin’s Argument (taken from the abstract [here.](http://www.oxfordscholarship.com/oso/public/content/philosophy/9780195078640/acprof-0195078640-chapter-12.html)) > [@](#): > > In this chapter, I continue to argue that naturalistic epistemology flourishes best in the garden of supernaturalistic metaphysics. I do so by presenting two epistemological arguments against metaphysical naturalism; the first argument is for the falsehood of naturalism, the second, and more developed, is for the conclusion that it is irrational to accept naturalism. Crucial to both arguments is the estimation of the value of a certain conditional probability, P(R/(N&E&C)), where (roughly) R is the proposition that our cognitive faculties are reliable, N is metaphysical naturalism, E is the proposition that our cognitive faculties arose by way of the mechanisms of evolution (i.e., the mechanisms to which contemporary evolutionary thought directs our attention), and C is a complex proposition stating what cognitive faculties we have and what sorts of beliefs they produce. In the second argument I contend that (1) it is quite plausible to think either that the rational attitude to take towards the conditional probability mentioned above is the judgment that it is low or that the rational attitude is agnosticism with respect to it, and, (2) in either case, the devotee of N & E has a defeater for any belief he holds, including N. Further, since this defeater is an ultimately undefeated defeater (as I argue), it is irrational to accept N, since it is irrational to accept any proposition such that one knows one has an ultimately undefeated defeater for it. For an entire paper on it from Plantinga, go [here.](http://www.calvin.edu/academic/philosophy/virtual_library/articles/plantinga_alvin/naturalism_defeated.pdf) My thoughts on Alvin’s argument are that it’s obviously false, and I agree with the commentary [here.](http://en.wikipedia.org/wiki/Evolutionary_argument_against_naturalism#Plantinga.27s_Argument) > [@](#): > > Fitelson and Sober also find fault with Plantinga’s presentation of the mechanisms of evolution and his analysis of the relation between belief and behavior. They point out that Plantinga may be correct that natural selection does not “care” about the truth or falsity of beliefs, but only behavior. However, it does not follow that true and false beliefs are equally likely to evolve. For example, in Plantinga’s tiger hypothetical (above), he posits three possible beliefs that would lead to Paul running from a tiger: > > Paul would like to be 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. > Paul 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. > (Implicit) Paul believes the tiger will harm him, and so he runs from it. > While all of these beliefs would lead to “correct” behavior from a natural selection standpoint, it does not follow that each belief is equally likely to evolve. > > Fitelson and Sober also argue that Plantinga’s argument does not show that proponents of metaphysical naturalism should a priori doubt all of their beliefs. This is because Plantinga’s argument rests in part on the idea that E&N defeat proposition R (i.e., that evolution combined with naturalism make it unlikely that “the great bulk” of the beliefs that humans have are true). Plantinga draws from this defeat the notion that proponents of E&N should not have confidence in any of their beliefs, including their belief in E&N. However, this does not follow. As Fitelson and Sober put it, “Even if E&N defeats the claim that ‘at least 90% of our beliefs are true,’ it does not follow that E&N also defeats the more modest claim that ‘at least 50% of our beliefs are true’.” In other words, until he can show that E&N defeats the proposition that “50% plus 1 of our beliefs are true,” Plantinga has not provided a reason for proponents of E&N to doubt their beliefs. Is naturalism defeated? Does Alvin’s argument stand up or do Fitelson and Sober destroy it? ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [March 15, 2007, 8:53pm UTC](https://boards.straightdope.com/t/evolutionary-argument-against-naturalism/396082/2 "2007-03-15T20:53:41Z")
I don’t see anything wrong with this argument (not having read the full paper.) I myself see epistemology as a conditional probability of our senses being correct: indeed, my personal tendency toward naturalism, (admittedly a peculiar naturalism that would indeed encompass any heretofore-regarded “supernatural entity” as “natural” insomuch as they communicate phenomenally,) is tempered by the knowledge that my senses themselves are derived from the natural world. Evolution doesn’t really have much to do with it, except that it goes a long way to explain how the senses are so go at gathering data from the natural world: indeed, that is why I weigh the conditional probability of the scientific epistemology so heavily, because it is one of the few epistemologies that achieves actual results. ---
**Author:** ![Sophistry\_and\_Illusion](https://avatars.discourse-cdn.com/v4/letter/s/b3f665/32.png) [@Sophistry\_and\_Illusion](https://boards.straightdope.com/u/Sophistry_and_Illusion)\ **Post date:** [March 16, 2007, 6:05am UTC](https://boards.straightdope.com/t/evolutionary-argument-against-naturalism/396082/3 "2007-03-16T06:05:27Z")
I haven’t read the article (although I have read similar arguments). If the wiki reconstruction of his argument is correct, then there is an obvious slide in his argument which, in my opinion, blunts its force. He starts out by talking about whether evolution would favor truth-apt cognitive machinery, but then develops his argument by talking about whether evolution would favor true beliefs, rather than merely adaptive beliefs. But evolution doesn’t select for beliefs at all. Our beliefs about the world are not (at least by and large) innate; they are learned through experience by means of our evolutionarily-produced cognitive mechanisms. And so what Plantinga needs to argue is that evolution could produce a cognitive mechanism which systematically produced beliefs which were false, yet somehow adaptive. The evolution of a system which in response to novel and unpredictable input from an ever-changing world produces systematically false yet consistenly adaptive beliefs would be miraculous; the chances are quite small. What would be the easiest and most obvious way for a cognitive system to produce adaptive beliefs? By producing true beliefs, which would accurately guide us in navigating the world and the hazards it contains. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [March 16, 2007, 8:43am UTC](https://boards.straightdope.com/t/evolutionary-argument-against-naturalism/396082/4 "2007-03-16T08:43:07Z")
I can’t honestly put my hand up and say I managed to successfully wade through all that verbiage, but it looks like it might be a variation on the theme of [CA120. An evolved mind is fallible, its conclusions untrustworthy.](http://www.talkorigins.org/indexcc/CA/CA120.html) ---
**Author:** ![FRDE](https://avatars.discourse-cdn.com/v4/letter/f/e68b1a/32.png) [@FRDE](https://boards.straightdope.com/u/FRDE)\ **Post date:** [March 16, 2007, 12:12pm UTC](https://boards.straightdope.com/t/evolutionary-argument-against-naturalism/396082/5 "2007-03-16T12:12:29Z")
It looks as if Alvin Plantinga has evolved to the point of incoherence. I hereby nominate him for the Laputan prize in applied impractical philology