Saturday, January 17, 2009

William Lane Craig on the Anthropic Principle

I heard Craig give this paper back in, I think, 1987. It is in response to the John Barrow and Frank Tipler book from that time.


Eric Koski said...

Of course, much has been written about this since, by Drange, Draper, Carrier, Stenger, and others. The argument makes at least some sense when cast as a Bayesian argument, in which case the critical issue seems to be: What are reasonable prior probabilities for the values of the fundamental constants? Craig and others offer us a picture in which candidate values for, say, the mass of an electron are laid out on a spinner from a children's game (Snakes and Ladders, maybe). Is this a good picture? Are the probability density functions for the different constants independent? Why isn't the prior probability of the ensemble of actual values equal to 1? Without any informed, rational way of assigning prior probabilities here, I don't see that the argument has any force at all.

Stenger raises the excellent additional point that there's no reason to assume that only universes resembling ours (the ones resulting from the alleged 'fine tuning') are universes in which life can arise.

When so much has been written about this, I wonder about the value of starting a discussion about it here.

jb said...

In an audio lecture or interview I heard by Dr. Craig recently, he acknowledges that the argument is less effective than it once was, and he had an answer for the more contemporary ideas on the subject. I wish I could easily figure out which audio file it was; I have so many stored on my mp3 player. I think it was on a Reasonable Faith podcast or something.

BTW, Frank Tipler has embraced Christianity since then.

Blip said...

Does any philosopher take the anthropic principle seriously anymore? It does seem a very confused principle.