Posts tagged ‘plantinga’

2012/03/16

Naturalism not actually defeated

So I have been bad about writing down things about this next Plantinga paper, largely because I have been making sure my healer looks good, and related endeavors. And working and stuff.

But anyway! The paper in question here is Plantinga’s “Naturalism Defeated“, dated 1994, which presents an argument I gather first presented in his “Warrant and Proper Function” (1993), and is apparently still one of his big talking points (2012).

The basic argument is pretty simple. If, it says, you believe both in evolution and in naturalism (which is the lack of supernatural things), then you are in trouble, because in the absence of supernatural intervention, evolution doesn’t reliably create creatures that are good at coming to correct conclusions, so you’re forced to conclude that your own conclusions aren’t reliable. This doesn’t mean that evolution-plus-naturalism isn’t true, of course, but it does suggest that one oughtn’t to believe it, in the same way that one oughtn’t to believe solipsism, radical skepticism, or that one is a brain in a vat, even though in some sense none of those can be refuted.

(I actually find it a little amusing here that the argument basically says that you shouldn’t believe evolution-plus-naturalism, because if it’s true your own reasoning processes don’t give you good reasons for belief, and you shouldn’t believe things without good reason; whereas as we saw last month he apparently thinks it’s fine to believe in god without good reason. But there ya go.)

Anyone who knows anything about evolution will have a hard time with that “in the absence of supernatural intervention, evolution doesn’t reliably create creatures that are good at coming to correct conclusions” part. As Plantinga puts it (rephrasing Patricia Churchland):

[T]he objective probability that our cognitive faculties are reliable, given naturalism and given that we have been cobbled together by the processes to which contemporary evolutionary theory calls our attention, is low.

On the face of it this seems silly; it seems immediately obvious that in the usual sort of Darwinian contest, having reliable cognitive facilities is better than not having them, so they will tend to evolve, subject to constraints about how expensive they are to build and operate, how well they are passed along to offspring, and so on.

But Plantinga attempts to make a case for it. He points out, with Churchland, that evolution selects only for behavior and not (directly) for belief. And Plantinga points out that for any example of a set of desires and true beliefs that lead to adaptive behavior, you can construct a set of different desires, and false beliefs, that lead to that same behavior.

Sure, not wanting to be eaten by tigers and believing (correctly) that they want to eat you will make you tiptoe around that sleeping tiger there, but so will wanting very much to be eaten by tigers, and believing (falsely) that they especially like to devour people who tiptoe! In his words:

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 that 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. . . . or perhaps he thinks the tiger is a regularly recurring illusion, and, hoping to keep his weight down, has formed the resolution to run a mile at top speed whenever presented with such an illusion; or perhaps he thinks he is about to take part in a 1600 meter race, wants to win, and believes the appearance of the tiger is the starting signal; or perhaps . . . . Clearly there are any number of belief-cum-desire systems that equally fit a given bit of behavior.

And that’s quite true. It’s pretty much irrelevant, though, since we’re not talking about the evolution of specific beliefs, we’re talking about the evolution of reliable or otherwise cognitive systems. It’s very hard to imagine a cognitive system which would reliably produce false but adaptive beliefs of this kind. Roughly, if Paul is crazy enough to think that the tiger is a cuddly pussycat that you pet by running away from, he probably thinks that alligators are treasure chests that you open by sticking your head in their mouths, or whatever, so he’s not going to be passing those crazy genes very far.

So that example is not very useful, because it talks about single beliefs, not about cognitive systems or methods of coming to have beliefs.

Plantinga comes close to realizing this, although he doesn’t quite get it.

A problem with the argument as thus presented is this. It is easy to see, for just one of Paul’s actions, that there are many different belief-desire combinations that yield it; it is less easy to see how it could be that most of all of his beliefs could be false but nonetheless adaptive or fitness enhancing. Could Paul’s beliefs really be mainly false, but still lead to adaptive action? Yes indeed; perhaps the simplest way to see how is by thinking of systematic ways in which his beliefs could be false but still adaptive. Perhaps Paul is a sort of early Leibnizian and thinks everything is conscious (and suppose that is false)… Perhaps he is an animist and thinks everything is alive. Perhaps he thinks all the plants and animals in his vicinity are witches, and his ways of referring to them all involve definite descriptions entailing witchhood. But this would be entirely compatible with his belief’s being adaptive; so it is clear, I think, that there would be many ways in which Paul’s beliefs could be for the most part false, but adaptive nonetheless.

This is somewhat plausible, and also somewhat beside the point again. Note that this time all of the false beliefs he gives as examples are (apparently) ones where the false part of the belief doesn’t impact action at all. So now he is pointing out that you can have lots and lots of false beliefs without being maladaptive, as long as those beliefs don’t influence your behavior.

How often does a false belief really not influence behavior? If I am an animist and think that everything is alive, isn’t it likely that I will tend to act differently toward things, and (assuming they aren’t really alive) that that will make me less efficient and effective? This seems likely at least if the predicate “is alive” actually has any content for me. If I think all of the plants and animals around me are witches, won’t I spend time placating them, or hiding my fear of witches from them, or whatever? Or at the very least worrying that they might convert into their true form while I’m not looking and cast spells or whatever it is I think witches do? Seems likely, and maladaptive at least to the extent of wasting time that I could have put to good pro-survival uses.

But again what we should be thinking about are cognitive systems rather than just beliefs. If we think about adaptive cognitive systems, it seems pretty inescapable that they will, to first order, tend to produce true beliefs about things that matter to behavior. And given that they do that to first order, it seems likely that at least some of the methods that they use to pare away false beliefs that impact behavior will also serve to pare away false beliefs that don’t. Not as efficiently, perhaps, since doing that isn’t of direct evolutionary value, but it seems quite plausible as a by-product.

That is, we first learn to find truths about things that will kill us if we get them wrong, but the methods that we use, the cognitive habits and structures and systems that we develop and evolve to do that, are likely to be good at finding truths in general; or at least there seems to be no reason to think they won’t be. So once I learn experimental science in a context where it does impact my survival, I am likely to do an experiment to confirm my belief that all these plants and animals are witches, and much to my surprise I will find they are not! And so I will be rid of that false belief, even if (somehow) the belief itself wasn’t hurting me any.

So it seems that the believer in naturalism and evolution really does have good reason to have a certain amount of faith in his own conclusions, since there is a good story that can be told about how evolution leads to reasonably reliable cognitive systems without any divine intervention.

(It’s an interesting question, actually, whether things are any better for the believer in divinely-infused knowledge, or whatever Plantinga would propose as an alternative to naturalism plus evolution. Is there any reason to think that such a person can tell true divinely-infused beliefs from false divinely-infused beliefs? The argument that the Divine would infuse only true beliefs, because the Divine is good, is very vulnerable to the argument that an evil Divine would likely have infused exactly that same “the Divine is good” belief into one, along with whatever false beliefs tickled the evil-Divine fancy; so one doesn’t really have any rational argument for one account over the other. On this argument it seems that this kind of believer is at least as badly off as the naturalist would be in Plantinga’s original argument.)

It’s perhaps worth noting that the bulk of Plantinga’s “Naturalism Defeated” assumes that the believer in naturalism and evolution actually accepts most of the argument of the paper, but after granting that naturalism plus evolution does yield the conclusion that human cognitive faculties are unreliable, then tries to squirm out of it by claiming in various ways that it’s okay to believe in them anyway. This part of the paper (which makes up at least 75% of it) is full of quaint symbology and meticulously organized discussions of what it means for something to defeat something else, and what kinds of things can defeat what other kinds of things, and whether and how defeaters can themselves be defeated, and so on.

And fascinating as that might be if you’re into such things (and I used to be, but now amn’t), it’s all entirely beside the point, because in fact naturalism plus evolution actually gives us a pretty good reason to believe in the reliability of our cognitive faculties. At least as good a reason, I suspect, as whatever Plantinga’s alternative gives him for believing in his…

2012/02/03

Is it rational to believe random stuff for no good reason?

So yesterday I got into the car to go get something from somewhere, and I heard the tail-end of an interview with some philosopher-guy. All they said in the twenty seconds I heard was that God and football are the main topics at Notre Dame, although there are a few others ha ha, and then they said his name is Alvin Plantinga, and he has a new book.

Thanks to the magic of the Innertubes, in this case the NPR app for the iPad, I was able to listen to the entire piece (and you can too if that link still works; it’s just six minutes). It’s Alvin Plantinga, who’s an Emeritus Professor of Philosophy at Notre Dame, talking in very general terms about how science and religion are compatible, and how in fact it’s “naturalism” (i.e. the idea that there are no “supernatural entities”, by which he means God, because no one believes in Santa anymore) that’s the weird belief, and that science is a great thing, but just limited in scope, and there are lots of things that you can’t scientifically prove, like the reality of the past (that is, the entire universe could have been created five minutes ago in exactly the state that we all remember, and you wouldn’t be able to tell), and (I’m guessing) the divinity of Jesus.

I’m always interested in religious people who claim to have a rational (or rough equivalent) argument for their religiousness, so I poked around the web a bit, and found a site that has a bunch of his papers, and I read a couple of them.

There’s some interesting stuff here, but I think he tends to (rather Searle-like) skip very quickly past the obvious problems with his theories, and dive into the complex and arguable ones instead. Admittedly those are more fun :) but…

On to the arguments! The first paper I read was “Theism, Atheism, and Rationality“; it’s intended as a response to the claim that “[a] person who believed without evidence that there are an even number of ducks would be believing foolishly or irrationally; the same goes for the person who believes in God without evidence”, and that therefore “one who accepts belief in God but has no evidence for that belief is not, intellectually speaking, up to snuff.”

He examines this first as a claim that the “theist without evidence” is violating an ethical or cognitive duty or responsibility that applies to any member of some cognitive or rational community, and that by violating this duty e opens emself to criticism and disapprobation by (other) members of the community, that being the way that communities work.

Plantinga’s first response to this is to note that he doesn’t exactly choose to believe in God. Although there may be “some sort of regimen” that he could use to eventually change or extinguish that belief, it’s not like if offered a million dollars he could just change his belief in a moment.

And that’s fair; no one needs to claim that he’s being irrational on purpose, I don’t think.

So what’s the alternative? The next possibility he considers is that, rather than choosing to do something wrong, perhaps the theist without evidence is defective in some way, broken, or ill, or otherwise malfunctioning. That’s all very well, he says, but the theist might also say that the atheist is broken or ill or malfunctioning or full of sin or whatever, and doing the wrong thing for that reason. How do we decide which one is actually malfunctioning?

(It’s interesting to note at this point that while he started out talking about someone who thinks it’s irrational to believe in God without sufficient evidence versus someone who thinks that’s fine, he’s now talking in plainer terms of atheist versus theist; that will become key a bit later.)

It’s easy for the theist, he says, in that correct functioning means functioning as God intended, and God wants us to believe in him, so believing in him is correct functioning. (Which makes alot of unwarranted assumptions about God and belief, but we’ll let that pass for now.) What, he asks, can the atheist offer instead?

Here Plantinga considers, and instantly dismisses, the right answer. The “atheological evidentialist objector” (love the phrase) “may be thinking of proper functioning as functioning in a way that helps us attain our ends“. And that’s basically right: for pretty much any plausible set of plans and goals and desires, believing stuff only for good reasons is much more conducive to attaining them than is believing stuff without good reasons (because it feels nice, or because you saw it in a dream, or whatever). If I believe in a traditional Christian God for no good reason, for instance, I will probably defer various pleasant things on the theory that I will be infinitely rewarded after death as a result; but if I don’t have good reasons to believe that, it’s quite likely false, and I will have deferred those pleasant things unnecessarily.

Plantinga, though, doesn’t look this deeply into the claim. He just notes that although the atheist may not want to believe in God, the theist probably does, so believing in God helps him attain his ends, and the atheist is just wishing that he wouldn’t. But that’s confusing “doing things that help me attain my ends in the long-run” with “doing things that I want to do right now”. One of the benefits of rationality, in fact, is just that it can help us see what will work out best in the long term, even when it’s not the thing we most want to do right now.

Next Plantinga does consider a version of the argument I give above:

A second possibility: proper functioning and allied notions are to be explained in terms of aptness for promoting survival, either at an individual or species level.

And that works, too, and in fact it’s a special case of the end-attaining argument above to the extent that in general our ends include individual and species survival.

Plantinga waves this one away, also, saying “the atheological objector would then owe us an argument for the conclusion that belief in God is indeed less likely to contribute to our individual survival, or the survival of our species than is atheism or agnosticism”, and concludes that that would be a hard argument to make.

I find this baffling! Suddenly, rather than replying to the suggestion that we shouldn’t believe in things (including God) for no good reason, he’s defending theism per se. Surely all that the atheological evidentialist objector (and note that Plantinga has dropped that middle word this time) has to argue is, not that believing in God is less survival promoting than not believing in God, but that believing things for no good reason is less survival promoting than believing things only for good reasons.

And doesn’t that seem awfully plausible?

Plantinga seems to have just dodged here, and that’s disappointing. He seems to entirely forgotten that he started out to respond to the claim that it’s irrational to believe in God without evidence, and reverted to just “well, you can’t prove that believing in God causes bad results!”, which is not the same thing at all.

The last paragraph of the paper is equally disappointing, raising a question that should be so obvious to any philosopher as to not even need asking. I’ll just quote the last three sentences:

The theist has an easy time explaining the notion of our cognitive equipment’s functioning properly: our cognitive equipment functions properly when it functions in the way God designed it to function. The atheist evidential objector, however, owes us an account of this notion. What does he mean when he complains that the theist without evidence displays a cognitive defect of some sort? How does he understand the notion of cognitive malfunction?

If only there were a vast existing literature, much of it not making reference to God at all, about what rationality and cognitive obligation and function and malfunction might mean! If only this vast literature were available in any decent university library, easily accessible by anyone in the Philosophy profession!

Oh, wait…

Next time: the next paper I read, in which Plantinga approaches some of these same things, and some different things, from a different angle, and raises some interesting questions, but still dodges the correct answer. His new book is apparently based on essentially the same argument.

Update: some stuff I forgot to mention. :)