Argument A. Meat can't think. My brain is meat. Therefore, what thinks in me when I think is not my brain.
A in Reverse: What thinks in me when I think is my brain. My brain is meat. Therefore, meat can think.
The proponent of A needn't deny that we are meatheads. Of course we are. We are literally meat (and bone) all the way through. His point is that the res cogitans cannot be a hunk of meat.
Both arguments are valid, but only one is sound. The decision comes down to the initial premises of the two arguments. Is there a rational way of deciding between these premises?
A materialist might argue as follows. Although we cannot at present understand how a hunk of meat could feel and think, what is actual is possible regardless of our ability or inability to explain how it is possible. The powers of certain configurations of matter could remain hidden for a long time from our best science, or even remain hidden forever. What else would be doing the thinking and feeling in us if not our brains? What else could the mind be but the functioning brain? The fact that we cannot understand how the brain could be a semantic engine is not a conclusive reason for thinking that it is not a semantic engine.
It is worth noting that the reverent gushing of the neuro-scientistic types over the incredible complexity of the brain does absolutely nothing to reduce the unintelligibility of the notion that it is brains or parts of brains that are the subjects of intentional and qualitative mental states. For it is unintelligible how ramping up complexity can trigger a metabasis eis allo genos. Are you telling me that meat that means is just meat that is more complex than ordinary meat? You might as well say that the leap from unmeaning meat to meaning meat is a miracle. Some speak of 'emergence.' But that word merely papers over the difficulty, labelling the problem without solving it. You may as well say, as in the cartoon, "And then a miracle occurs." But then it's Game Over for the materialist.
Our materialist would do better to insist that unintelligibility to us does not entail impossibility. Our inability to explain how X is possible does not entail that X is not possible.
My response would be that while unintelligibility does not entail impossibility, it is excellent evidence of it. If you tell me that a certain configuration of neurons is intrinsically object-directed, directed to an object that may or may not exist without prejudice to the object-directedness, then you are saying something unintelligible. It is as if you said that.5 volts intrinsically represents 1 and .7 volts intrinsically represents 0. That's nonsense. Or it as if you said that a pile of rocks intrinsically indicates the direction of the trial. (See The Philosophizing Hiker: The Derivative Intentionality of Trail Markers.)
No rock pile has intrinsic meaning or intrinsic representational power. And the same goes for any material item or configuration of material items no matter how complex. No such system has intrinsic meaning; any meaning it has is derived. The meaning is derived either from an intelligent being who ascribes meaning to the material system, or from an intelligent being whose purposes are embodied in the material system, or both.
Thus I am rejecting the view that meaning could inhere in material systems apart from relations to minds that are intrinsically intentional, minds who are original Sinn-ers, if you will, original mean-ers. We are all of us Sinn-ers, every man Jack of us, original Sinn-ers, but our Sinn-ing is not mortal or venial but vital. Intrinsic, underived intentionality is our very lifeblood as spiritual beings.
So if the materialist says that the brain means, intends, represents, thinks, etc., then I say that makes no sense given what we understand the brain to be. The brain is a material system and the physical, chemical, electrical, and biological properties it and its parts have cannot be meaningfully predicated of mental states. One cannot speak intelligibly of a voltage drop across a mental state any more than can one speak intelligibly of the intentionality of synapses or of their point of view or of what it is like to be one.
Of course, the materialist can pin his hope on a future science that understands the brain in different terms, terms that could be sensibly attached to mental phenomena. But this is nothing more than an empty gesturing towards a 'possibility' that cannot be described except in the vaguest terms. It is nothing but faith, hope, and hand-waving.
There is also the dogmatism of the materialist who insists that the subject of thinking must be the functioning brain. How does he know that? He doesn't. He believes it strongly is all.
So I give the palm to Argument A: Meat can't think. My brain is meat. Therefore, what thinks in me when I think is not my brain.
I do not absolutely foreclose on the abstract possibility that there be thinking meat. For I grant that unintelligibility to us is not invincible proof of impossibility. But when I compare that vaguely described abstract possibility with the present certainty that matter as we know it cannot think due to the very unintelligibility of the idea, then the present certainty wins over the abstract possibility and over the faith and hope of the materialist.