April 22, 2012
At the 2012 Greer-Heard Point-CounterPoint Forum last week I teamed up with Gary Habermas and Peter Kreeft to debate Michael Shermer, Victor Stenger and Keith Parsons on the reality of life after death. It was an exciting time and, from my perspective an that of many who attended, things really went well.
There was one thing that happened, however, that time did not allow me to comment on. This was an assertion by Shermer that evolutionary explanations of theological and ethical beliefs/behaviors are readily available, followed later in the debate by another claim by Shermer to the effect that Kantian objective intrinsic values and moral laws exist and can be known without the need for a God to ground either.
Now, while these two claims are strictly logically consistent, the former provides a substantial undercutting defeater for the latter. Here's why:
If our moral beliefs/behaviors resulted in our struggle for survival in light of the need to feed, fight, flee and reproduce, then those beliefs/behaviors do not track truth and are not counterfactually sensitive to it. Thus, suppose that in our world, the Kantian dictum to treat people as ends in themselves (e.g., don't lie to or kill or be racist towards them) is actually true.
Now consider a Twin Earth just like ours but in which these dicta are false. In Twin Earth, we would have exactly the same moral beliefs/behaviors; that is, our beliefs/behaviors would be ours whether or not they were true. In another possible world in which those beliefs/behaviors did not serve survival needs, then we would not have them. Thus, they track survival not truth.
It follows that if an evolutionary account of moral beliefs/behaviors is accepted, these constitutes an undercutting defeater for the reliability of our moral belief forming mechanisms and our action dispositions.
There could still be an objective moral law, but it would be sheer coincidence if our beliefs/actions comported with it.