Evolution is a defeater for naturalism?

 Alvin Plantinga's Argument

In the early 2000s, I went to hear Alvin Plantinga speak at the University of Wisconsin. He was arguing that believing in naturalism (everything came about through natural laws and processes) was a defeater for believing in evolution. If you believe in evolution AND you believe that humans have the capacity to reason correctly, then it is more probable that there is a creator of some kind. Because evolution and naturalism don't give you any reason to conclude that our ability to reason leads us to true knowledge--only to reproductively useful knowledge.

 

I spent a lot of time with his argument, and with various responses to and criticisms of his argument. I think it is pretty strong, and that most of the criticisms subtly fail. Yet twenty years later I find myself an atheist. I always was a naturalist and a believer in evolution. Those are very Mormon compatible positions. I spent hundreds of hours trying to figure out what material Gods would be like, and how and why we would want to worship and emulate them. If there are Gods, I'm confident they are material and natural--if in some way we don't fully understand--or they are arbitrary, beyond us, and not worth my energy to try to reason about. I can obey or not, but it will never make rational sense because they are beyond reason by definition.

Further, I was moved by the New God Argument, which continues to be refined over time. I still think aspiring to compassion, creation, and benevolence are admirable, the way I want to live, and the way humanity will thrive into the future. I don't currently see any possibility of Gods influencing or interacting with humanity through a Big Bang universe creation, and I find the Simulation Hypothesis dystopian and nihilistic (but that's too big an aside), so I have lost interest in the implications of the New God Argument that I formerly found most compelling. But here I wanted to briefly share my new take on Plantinga's defeater.

Only certainty is defeated

Most of the responses to Plantinga's argument try to take on his premises or his formal logic. I have landed in a different place. I grant every one of his premises, processes, and conclusions. If there is no creator that made reason true and valid, than we can't trust the absolute validity of reason developed through evolutionary processes. He's right. Evolution makes things functionally successful for the purpose of propagating the species.

 

So if evolution did make reason, then reason can be trusted as far as it makes humanity propagate effectively. It is another of the emergent phenomena that have arisen through the expression of nature in humanity. We can trace its development back through time, from modern science back to Socrates, Confucius, and beyond. We can measure how other animals make decisions and see in it bits of human reason. Reason has given us tools to spread humanity across the globe and to number in the billions. Whether we thrive into the future or not may well depend on how we follow the reason that tells us we need to be much better stewards of the Earth, and much more equal and compassionate in how we treat one another. But our reason may not be fully trustworthy. There is no guarantee that it is. Naturalism and atheism don't need reason to be perfect or certain, even if many of the most vocal naturalists and atheists insist it is. Evolution doesn't need them to be right--just effective at passing on their genes. But reason seems to work pretty well--just like I might expect from an evolved tool.