Tuesday, October 20, 2009

Naturalism without causal closure?

The problem has to do with causal closure. Presumably, you have matter moving in the universe without purpose, producing stars, then planets, then water, then life, (one-celled biological systems), then fish, dinosaurs, amphibians, mammals, primates, and then people. Now people presumably act for reasons, and suppose that mental causation is causally basic. Talk about a person becoming persuaded that atheism is true because of evidence from evil is not macro-talk for a physical process which is blind at the basic level but has mental characteristics as system features.




The question is how did tihs happen? What changed the physical order to make it possible for reasons to become basic causes. If people are acting for reasons, then either you've got to reduce reasons out of the causal transaction, or you've got matter acting in ways it doesn't ordinarily act when it's in a brain as opposed to when it's in a rock. Emergence of other kinds is one thing, but emergent laws? I suppose you can say that it's just a brute fact that matter is going to behave differently once a brain of a certain complexity emerges. But isn't this whole thing more probable given theism than it is given ordinary naturalism.



But suppose our motto is "anything but God." Well, then meet C. S. Lewis. According to his autobiography Lewis accepted the overall contours of the argument from reason, but he didn't become a theist at that point. No, he became an absolute idealist. He found other reasons for rejecting idealism and for becoming a theist. So while his acceptance of the AFR certainly helped to move him in the direction of theism, there were alternatives to traditional theism available to him. So while the AFR helps to get rid of certain very popular positions contrary to traditional Abrahamic theism, it doesn't eliminate all of them, nor did it persaude even C. S. Lewis to do so.



To avoid a large explanatory problem, however, I think people who are naturalists are best advised to defend versions of naturalism that include the three doctrines of mechanism (nothing mental at the basic level), causal closure of the physical, and supervenience.

10 comments:

Trav said...

Great post Victor.

Gordon Knight said...

Glad to see Absolute Idealism getting a mention.

Teague Tubach said...

That was a nice post. What if the naturalist just doesn't have the answers to these questions? You wrote "But isn't this whole thing more probable given theism than it is given ordinary naturalism." but surely you don't think that explanatory power is linked to truth?

Anonymous said...

What do you mean by explanatory power not being linked to truth? What does it mean for something to be "linked to truth?" And I'm curious how this is relevant?

Victor Reppert said...

I believe that if an event in the world is more likely given hypothesis A than hypothesis B, that is evidence that hypothesis A is true and hypothesis B is false. I'm a Bayesian and a subjectivist about prior probabilities.

ttubach said...

Thanks Vic, I'm not necessarily opposed to that, yet it has been my experience that false hypotheses can have a lot of explanatory power, and true hypotheses can have none. Maybe a 'prior probabilities' post is in order? I wrote a paper on this once, I'll try to dig it up and post it on my blog.
Anon - read Vic's second paragraph and pay close attention to the last sentence.

Mark said...

I really fail to see how theism is supposed to solve this problem. Since God is supposedly an incorporeal mind causing all sorts of physical events, you still have to explain what gives rise to God's causal efficacy over the physical universe. Maybe you'll reply that God's existence and therefore his causal powers are necessary, and so is in no need of explanation. But without independent motivation for this claim, you could just as easily posit that necessarily physical structures like brains summon into being immaterial souls with brute causal powers. I would much sooner believe that brains necessarily give rise to magical ghosts than believe there's a super-magical ghost who's existed since the beginning of the universe!

Victor Reppert said...

But on a theistic scenario, and all other scenarios that make something rational metaphysically fundamental, you don't have to transition fro a situation in which reason is absent to one in which it is present. "In the beginning was the word." That which is self-existent has rational characteristics.

Terms like "super-magical ghost" obscure the discussion. They sound good to fellow members of the Church of the New Atheism, but they don't do much for people trying to think this through from the other side.

Mark said...

You seem to be erroneously suggesting that there's some important difference between the mysteriousness of a universe where irreducibly mental causation is always there and a universe in which it only springs up after several billion years with human brains. Mental causation is just as "fundamental" in the latter universe as in the first - it just requires different special conditions (like the evolution of brains) to be met before it becomes active. The real question, the real mystery, is how there could be such high-level causal relationships between minds and complex arrangements of physical matter. And this is just as much, if not more so, a question on theism as it is on any other position.

ttubach said...

cranes > skyhooks