Putnam's Evolutionary Argument Against Naturalism

Alvin Plantinga has a famous argument whereby he argues that strict darwinian evolution robs us of our ability to trust our own reason. He says, in essence, that all claims of knowledge conform to some idea about 'properly functioning rational faculties.' Using Bayesian logic, he tries to demonstrate that evolution's survival-based picture of human nature and proper function robs us of our ability to trust any of our rational faculties. It is an interesting and powerful argument, but I've never found it convincing. It think Plantinga aims too high, trying to use evolutionary theory to undermine our trust in ALL of our rational faculties.

Hilary Putnam has a similar argument that I think is much stronger, and should be persuasive. He argues that strict darwinism undercuts our ability to trust science. The intelligence we evolved, was developed under certain selection pressures, none of which were likely to produce a being that could think about the big questions of life and come up with right answers. Putnam thinks it is highly unlikely that the same selection pressure that makes us good at making fires or hunting would simultaneously make us very good at understanding things like gravity or the nature of light. As such all of our theories are suspect, including the theory of evolution itself. The point is not that evolutionary theory is false, Putnam certainly believes in natural selection. It is simply that there must be something extra added to our picture of human nature, that makes truth something central to our being. Without this, much of what we think we know comes into question.