Archive for March, 2012

2012/03/18

The D’Lish Dish

I stopped on a whim today, between the post office and the UPS store, because there was a food truck that I didn’t remember seeing before, parked at the bottom of the big park / soccer field / walking track / gathering place in town (at the other end of which is the town stage where the little girl’s ballet performances used to be, back in Ancient Times). In the summer there’s an ice cream truck that parks up closer to the other end, by the little pavilion, but today there was a food truck down at this end. And the sign looked interesting, and I’d told myself I would treat myself to something novel and lunch-like while I was out doing errands.

So it was perfect.

And it was a great surprise. :) Not just a hot dogs and “do you want sauerkraut or onions on that” and soda truck, although that would have been enough for me, but instead it was Sharion’s D’Lish Dish, and I expect that was Sharion herself telling me what they had and asking if I wanted lettuce and tomato, and saying that it would take awhile because everything was made fresh. And she was most definitely right there behind her eyes, as you’d expect from her story of herself there.

And the BBQ’d Beef Sandwich (with lettuce and tomato, and cheese, and waffle-cut fries with ketchup and a pickle slice on the side) was very very fresh, and extremely delicious, and worth every minute spent leaning on the metal stair-railing, listening to passing cars and to Sharion’s little gasoline generator chuffing to itself, and watching people walking and jogging and wheeling baby carriages by on the track, and feeling the sun and the wind, and closing my eyes and half-dozing standing there.

Every minute.

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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…