Dennett, Harris, Hitchens vs. Boteach, D'Souza, Taleb

I don't usually outsource my reviews to other (better) bloggers than myself, but I'll make an exception in this case and direct you to PZ's review of this debate. I have very little to add to that review, except to contest the idea that Hitchens successfully "[r]efutes the fine-tuning argument" and to say that I found Robert Wright's perspective refreshingly novel rather than muddled. I'd argue (presumably contrary to PZ) that we need more agnosticism and deism in God debates.

Dennett vs. Plantinga in Chicago, IL

In this presentation (which mutated into a debate) one certainly gets the sense that Alvin Plantinga is just plain bluffing.  He throws up plenty of nifty maths onto the whiteboard, but these serve primarily to obfuscate his false premises rather than bring enlightenment to the audience.  Plantinga’s evolutionary argument against naturalism was thoroughly rebutted some time ago, and he seems even not to be unaware of these cogent criticisms of his position. Moreover, he seemed not to notice when Dennett explicitly rejected and refuted his key premise.

A bit of background is necessary here, because Plantinga's argument is fairly technical and most people don't much grok maths, especially Bayesian probabilities.  Suffice to say that for his argument to go through he must show that humans most always form true beliefs about the world [ P(R)≈1 ] and that probability of this happening if metaphysical naturalism and evolutionism are true is low [P(R|E&N)≈0].    

Alas, Plantinga fails to substantiate either of these claims in anything like a rigorous logical fashion.  He more or less assumes the truth of the former premise and pretty much hand-waves his way to the latter.  When a brilliant logician such as Alvin Plantinga is waving his hands instead of outlining a deductive argument, well, caveat emptor.

A couple points must be made here.  Metaphysical materialists cannot assume P(R)≈1 since we believe that all talk of gods, spirits, ghosts, chakras, etc. is all so much bunk.  People around the world make up all sorts of wacky beliefs about disembodied minds and imaginary forces emanating therefrom, thus, P(R) is evidently nowhere near unity.  Moreover, since most religions (with a few interesting exceptions) assert that all other religions make up all sorts of untruths about the world, which are integrated into their devotees worldviews, it seems odd for any religious person to argue that humans almost always form true beliefs about the world. Finally, it should be evident from the abundance of material at sites like http://www.snopes.com/ and http://www.nizkor.org/features/fallacies/ that we humans are prone to all manner of irrational thinking, not least of which is a tendency to attribute agency where none exists.

Secondly, while the probability P(R|E&N) is nowhere near unity, it is neither so low as to allow Plantinga's argument to go through.  The crucial question here is whether we would expect naturalistic evolutionary mechanisms to select for true beliefs over false ones.  This question is not nearly so simple as it sounds (or as Plantinga's treatment suggests) but it should be fairly obvious that it is generally far easier to program a neural network to solve problems of adaptivity by providing adaptive goals and good data than by providing maladaptive goals and bad data.

Dennett managed to raise some of these points by way of an awkward analogy, but to be fair he was dealing with a mathematical smokescreen while standing up.  This is something no one should be expected to do.  

Dennett vs. McGrath in New Orleans, LA

This debate could have been better than it was if only the speakers had been given more of an opportunity for direct cross-examination.  As it was, they only went head-to-head on a few issues, most notably that of the validity of meme theory as a viable paradigm for the social sciences to research.  McGrath manages to sound fairly erudite when talking on such matters, as when he quite cleverly quipped that memetics is not awaiting its Watson and Crick, but rather its Michelson and Morley.  Of course, a thoroughgoing scientist would have to leave both possibilities wide open, but McGrath seems to disregard the former altogether when he peremptorily rejected memetic theory (along with religious unbelief more generally) without first examining its rational foundations.

Dennett (alas) doesn’t fully elucidate the key point at issue here, which is that while some genes and memes may be merely parasitic others are far more symbiotic with their hosts.  Just as we humans cannot live without our inborn intestinal fauna, so also we could not thrive as ultra-social civilizational beings without any number of meme-complexes, such as language, ethics, and law.  However, just as many protozoa are not particularly helpful to human hosts, so also there are ideas which, while spectacularly successful as self-replicators, are not particularly helpful to human minds and bodies (e.g. capital punishment for apostasy, blasphemy, carving deities, etcetera).  Such parasitic ideas as these survive not by conferring survival benefits directly upon their host, but rather by creating strong incentives for memetic replication along with threats of reprisal against those who fail to adopt them. 

McGrath utterly fails to appreciate the distinction between adaptive (symbiotic) memes and maladaptive (parasitic) memes, and thus cannot see how it might be that some memes spread because they are true and useful to their hosts, whereas others will spread merely because they well-designed to do so.  The lesson here is that a little humility goes a long way in allowing one to see the full import of a novel and difficult idea.  Perhaps more importantly, one ought not create straw-man simplifications of one’s opponent’s views and then crow proudly about burning them down.

Overall, though, this was a good exchange between two deep thinkers who manage to keep cordial even as they are lobbing rhetorical barbs.  Not a bad listen.

Overall rating: 3.5 stars