Reppert and CS Lewis: The "Grab bag" and Reduction

I read Victor Reppert's book, C.S. Lewis's Dangerous Idea over break. As Lewis and his writings continually inspire and challenge me, it was very cool to read a book attempting to formalize Lewis's argument from reason. The gist of the book is that Lewis's argument (which I will describe in a second) is actually a good analytical philosophical argument. Lewis argued in the 3rd chapter of Miracles something like this:

1. Naturalism tells me that my brain is no more than an aggregate of molecules interacting according to nonrational causes.
2. If the thoughts in my brain are caused by nonrational causes, then I have no reason to trust their rationality.
3. Thus, if naturalism is true, then I have no reason to trust my thought process that informed me it is true.

While I enjoyed Reppert's attempts to formalize Lewis, it felt unsatisfying. Reppert offers 7(!) different formulations. My initial reaction was that these werenothing more than a "grab bag" of the traditional objections to reductive naturalism.

However, on reflection, I realized that this "grab bag" is actually not to be despised. Assuming that the world is structured the way Lewis thought it was, a reductive program would explain most phenomena, but not all. There would be various unexplainable phenomena scattered around, troubling us. That is indeed what we see. While I am still dubious of the stylistic value of offering 7 equally competing formulations, I respect the "grab bag" much more now.