The weaker and the stronger Anscombe claims

 I think everyone working on the Anscombe essay (that includes one Victor Reppert) has been making a mistake in not distinguishing between Anscombe criticizing Lewis for, for example, not making the distinction between GC and CE on the one hand, and saying, and making this claim at the end of her piece:

I do not think that there is sufficiently good reason for maintaining the “naturalist” hypothesis about human behaviour and thought. But someone who does maintain it cannot be refuted as you try to refute him, by saying that it is inconsistent to maintain it and to believe that human reasoning is valid and that human reasoning sometimes produces human opinion.

That seems to imply a refutation, and a claim that once Anscombe's distinctions are drawn, the naturalist is off the hook. Lewis comes back and says "OK, I see your distinctions, but you're actually making it worse instead of better for the naturalist." At the end she goes from saying "You didn't refute the naturalist for these reasons," to "You can't refute the naturalist this way." It's more than just a correction. McGrath, who sees the whole thing as a win-win on both sides (just a friendly correction), overlooks this passage. But she doesn't repeat the more ambitious claim. 

Does Darwinian biology explain the mind?

 The whole thrust of Darwinian biology, which is the big naturalist selling point, is to replace mind explanations with mindless ones, rendering mind explanations perhaps useful but not literally true. If Darwinian biology explains the mind, therefore, it explains it away. It explains it in such a way that mental explanations are not literally true. So, if Darwinian biology is comprehensive, then it follows that it is not literally the case that Darwin inferred his theory of natural selection from the evidence, of, for example, finch beaks in the Galapagos Islands. So, you have to be the kind of naturalist that says that Darwinian biology does not explain the human mind. I know of someone who says this who doesn't believe in God or anything like God, but last I checked he had made a lot of people in the naturalist camp really mad for saying this sort of thing. Do naturalists want to include Nagel in their club, or keep him out?

What, exactly qualifies as naturalism? And what did C. S. Lewis think he had refuted?

 In defending the central argument in the third chapter of Miracles, we have to ask exactly what Lewis meant by naturalism when he said that naturalism is self-refuting. David Kyle Johnson thinks there is a standard definition of naturalism--an entity is natural if it is part of the universe, and naturalism is the view that only the universe exists. It has nothing to do with whether mental states are fundamental to the universe or not. Hence an argument that shows that there must be basic mental causes would not be sufficient to refute naturalism, since there are versions of naturalism where this is not denied. 

David Kyle Johnson, "Retiring the Argument from Reason," Philosophia Christ Vol 20, no. 2., (2018). 

But, in fact, the difficulty in defining naturalism is widely noted, and so far as I can tell, there is no standard definition. Alvin Plantinga defines naturalism as the view that there is no God, or no being like God. But what is God-like enough to be a problem for naturalism? 

Rickabaugh and Boras state that naturalism is a thesis about ontology, but is also a thesis about explanation. They note: 

The distinctively scientific mode of explanation is subpersonal and mechanistic.16 To give a mechanistic explanation of some phenomena (for example, change in location) is to cite a property of an object (for example, the mass of a body) together with a natural law (for example, Newton’s inverse-square law) describing how things with that property regularly behave. Such laws describe the most general patterns of variation in nature, based on the inherent tendencies of things. Mechanistic explanations thus tell us what we can expect to happen automatically (deterministically or probabilistically) and, as it were, of its own accord. That is, whether prior events strictly necessitate or fix the chances of a future event, still that event is the automatic result of nonrational causes. Deterministic laws predict a fixed outcome for phenomena that fall under their jurisdiction. Probabilistic laws, by contrast, assign a probability to all possible outcomes, and leave it to chance to resolve which comes to pass. Mechanistic explanations thus tell us that some phenomenon occurs because the state of the universe and the laws of nature necessitate it or make it somewhat likely. Here is our point: the central idea of naturalism (at least with respect to explanation) is that mechanistic explanation is in principle complete, that is, sufficient to explain everything that needs explaining.

16. The account of scientific explanation in this paragraph and the next follows Richard Swinburne, The Existence of God, 2nd ed. (New York: Oxford University Press, 2004), 26–35, which is in turn based on the classic exposition in C. G. Hempel and P. Oppenheim, “Studies in the Logic of Explanation,” Philosophy of Science 14 (1948): 135–7

Brandon Rickabaugh and Todd Boras, "The Argument from Reason and Mental Causal Drainage: A Reply to Peter van Inwagen," Philosophia Christi vol 19, no. 2, 384. (2017). 

Lewis presents naturalism and supernaturalism as two options, so based on that you might think that he would be happy with Johnson's definition. However, Lewis also has a chapter on "Christianity and Religion" in which he argues against pantheistic views, and there he does not use an argument from reason. These pantheistic views include a position he once held, and the position he adopted once he became persuaded that naturalistic views "leave no room for an adequate theory of knowledge." That is, he became an Absolute Idealist. According to Absolute idealism, God is not distinct from the universe, and so by Johnson's definition, it qualifies as a form of naturalism. 

In any event, in the name of naturalism many people hold a position that says that the base level is mechanistic (in the sense described), the base level is causally closed, and whatever else there is supervenes on the base level. Most of them call the base level physics, which makes them physicalists. If these positions are refuted by the argument from reason, then it is hard to call the argument from reason a failure, even if it leaves space for people to depart from that position without embracing theism. After all, that is just what C. S. Lewis did when he was first convinced that naturalism as he understood it did not hold up. As he said "I didn't want there to be a God, I didn't want the universe to be like that."  Oh wait, with a tense change, that's Thomas Nagel. I apologize for the confusion. 

I have decided to renew this blog

 I have been spending quite some time thinking and working through the argument from reason once again. Maybe there will be a sequel to my C. S. Lewis's Dangerous Idea. In the last 10 years, I have been in an exchange with David Kyle Johnson which began in Gregory Bassham ed. (Rodopi-Brill, 2015), and followed that up with an essay called "Extending the Debate on the Argument from Reason," which came out in Philosophia Christi vol 20 issue 2. I have been doing some things on the related matter of the Anscombe Legend, and I am working on a response to Peter van Inwagen's critique of the AFR, and recently did an interview on the argument with Parker Settecase, found here.