>>>This is a post on my first-ever brush with serious, academic philosophy of religion in the form of Alvin Plantinga.; I did in fact go to the talk and write about it, though that post actually turned out less interesting. Since then, I have learned that unlike a lot of things Evangelicals say to promote their guys, what they were saying about Plantinga is true: he is in fact the number one philosopher of religion on the planet. I still think he’s an embarrassment when he tries to talk about science. On the other hand, his stuff on possibility brings valuable clarity to the subject and his stuff on epistemology is at least worth reading (which isn’t a small deal, in the age of publish or perish).<<<

When I got up to go to breakfast this morning, I was treated to a series of sidewalk chalking announcing a talk, this Thursday and Friday, titled “Evolution v. Atheism” by a philosopher named Alvin Plantinga. I briefly wonder what the title could mean, and make a mental note to see it.

Then I see flyers with “Student Impact” (Madison’s Campus Crusade chapter) written on them. This prompts me to Google the guy, which got me a list of his writings.

First, a paper arguing that if one accepts Christianity, evolution is probably but not definitely false. Early on, he says this about the debate:

the philosophers and theologians don’t know enough science

Then, after a long theology-based discussion:

There isn’t the space, here, for more than the merest hand waving with respect to marshalling and evaluating the evidence.

Yes, if you want to be wise, know that you know nothing. And be honest about it!

Then reading this lecture outline, I realized I was reading the guy Joe Carter cited as having proven that evolution won’t produce reliable belief-forming mechanisms. Plantinga argues purely naturalistic evolution is self-defeating for this reason. Talking about beings pr

Suppose we think, first, not about ourselves and our ancestors, but about a hypothetical population of creatures rather like ourselves on a planet similar to Earth.

…Probability… that their cognitive faculties are reliable?

Not as high as you might think. Beliefs don’t causally produce behavior by themselves; it is beliefs, desires, and other factors that do so together. Then the problem is that clearly there will be any number of different patterns of belief and desire that would issue in the same action; and among those there will be many in which the beliefs are wildly false. Paul is a prehistoric hominid; the exigencies of survival call for him to display tiger avoidance behavior. There will be many behaviors that are appropriate: fleeing, for example, or climbing a steep rock face, or crawling into a hole too small to admit the tiger, or leaping into a handy lake. Pick any such appropriately specific behavior B. Paul engages in B, we think, because, sensible fellow that he is, he has an aversion to being eaten and believes that B is a good means of thwarting the tiger’s intentions.

But clearly this avoidance behavior could result from a thousand other belief-desire combinations: indefinitely many other belief-desire systems fit B equally well. 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 the confuses running towards it with running away from it, believing of the action that is really running away from it, that it is running towards it; or perhaps he thinks the tiger is a regularly reoccurring 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.

Trying to combine these probabilities in an appropriate way, then, it would be reasonable to suppose that the probability of R, of these creatures’ cognitive systems’ being reliable, is relatively low, somewhat less than 1/2.

This is ludicrous. Some of Plantinga’s proposals just don’t work. In the case of wanting to be eaten, Paul is more likely to walk away slowly than to run. Even if it works once, it won’t necessarily continue to work. If Paul keeps seeing tigers that are unlikely to eat him, he might give up finding the ideal case and try his luck with the next tiger he sees. Furthermore, beliefs have to produce useful behavior in many situations, not just one. What happens when a Paul with one of these complexes must consider the possibility of a friend (or enemy) being eaten? Finally, even if there are many viable but complex mechanisms, the chance of evolution stumbling upon them is low.

This isn’t to say evolution would necessarily give us perfect mechanisms, just pretty good ones. But it makes no sense to throw out all our beliefs for this reason. After all, no one would insist that someone who admits, “I tend to think I’m pretty rational, but I admit I’m sometimes let astray by my personal biases” abandon all beliefs because they could result from biased thinking.