Thursday, October 05, 2006

The Reliability of Rationality Argument

For some reason, philosopher/theologian Alvin Plantinga is famous for his defenses of theism.

One argument that I've encountered once or twice is Plantinga's argument against naturalism. It argues that we should expect a low probability that evolution gave us reliable faculties for rational thought. The technical details of his argument have been well-refuted.

The first problem is that, frankly, human rationality isn't particularly reliable (as Plantinga himself demonstrates). However, any evolutionary process that creates thinking creatures is bound to create them with at least some rational capability. Without such capability, knowledge would be impossible, and the thinking process would have no advantage. In other words, it is all but certain that evolution would provide us with at least partial rationality.

Humans are capable of intuiting a distinction between the rational and irrational, and this provides a base from which they can amplify their rationality. This is much in the same way that humans find it difficult (non-intuitive) to do advanced mathematics, but they can succeed in this process through writing, symbolic manipulation and repetition. Thus, even having some rationality provides the necessary basis for high-reliability rationality.

The second problem is that Plantinga is claiming that we are more likely to be rational if theism is correct. This is rubbish. Introducing God removes any causal link between us and the deity that created us. Simply put, God isn't explanatory of our rationality because theism doesn't predict our rationality. As usual, theists can tune their theology so that we see what we see (e.g., humans are rational and fish aren't), but they never ever get any actual predictions, and their fine-tuned God accounts for exactly what we know to date, and never one thing more.


Tom Clark said...

Thanks for your comments on Plantinga - I'll check out Sober et al's paper. And yes, I wish Plangtinga would specify just how god secures our rationality in a way that evolution doesn't.

Keep up the good work!

Tom Clark
Center for Naturalism

Doctor Logic said...

Hi Tom,

Thanks for stopping by!