-Metaphysics claims to be structural to physics and the natural sciences.
-The first argument for metaphysics is that science itself is nothing like the things any science studies: it develops logically, and therefore by non-physically reversible or blockable processes; it’s progressions have logical necessity even when they are falsifiable; it s built up from observation, abstraction, propositions, judgments, and group consensus; it is an action with a social dimension and structure (science is “the scientific establishment” – no other methodological unity is plausible). Nothing in nature is like this.
-“We know the same theorem because out brains fired in relevantly similar ways”. But then why aren’t all the similar actions of our bodies leading to this? You can make your process of digestion as relevantly similar to mine as you like, why is believing the same theorem a possibility while digesting the same hot dog isn’t?
-Either the theorem in your head is numerically the same as mine, or we share something that is not one in number. Either way, it’s hard to see how this is anything recognizably natural.
–William James: thought is a process of the brain, but it is separable, and this because even physical processes are manifold: (a) Lifting proceeds from a crane, (b) a shot proceeds from pulling the trigger, (c) burning proceeds from orienting the magnifying glass in the right position. Naturalism rests on the illicit assumption that thought only proceeds from the brain in the first sense.
-But (a) is the simplest assumption and so is preferable to the others. Even if this were true, one could not point to the track record of taking it as true to prove that it is the simplest assumption. It is arguably the most complex assumption since the more complex the assumption the more it rules out, and (a) rules out many more possibilities than the others. B and C allow for all the truths of science to be true and the subsistence of mind and of spiritual beings also.
-Naturalism identifies possible truths with possible brain structures. This clearly won’t work since it would mean that one could wire a brain any way he likes and preserve truth detection. You might as well say you could wire a radio any way you like and preserve signal detection, or program a translation program any way you like and preserve accuracy. First epicycle: the brain structure must be adaptive. Problem 1. 100,000 years of human evolution is a blink of the eye in terms of the evolutionary histories that we understand best, and so it’s hard to appeal to the better evidence in evolution to prove adaptability. Problem 2. to say the brain is adapted means it is attuned to some feature of reality. Returning to James’s metaphors, which is most apt to a system that is being understood as attuned to some exterior reality? Steam isn’t attuned to boiling, but a radio is attuned to signal detection. If the mind arises from body, it arises more like a song from the radio than like steam from a kettle.