A "lively" exchange, shall we say. From Churchland's response to McGinn's review:
Nobody in neuroscience needs McGinn to tell us that structural correlates of a function do not ipso facto explain that function. His sermonizing is just so much spit in the wind. What he fails to get is that sussing out structure is often a major step forward in sorting out mechanism. Famously this was so when Watson and Crick figured out the structure of DNA. Neither they nor anyone else supposed that the mechanism of how proteins got made could therefore just be read off the helical structure. First, a lot more had to be discovered, such as the role of RNA, the existence of both messenger RNA and transfer RNA, the role of ribosomes, and a whole lot else besides. But discovering the helical structure of four base pairs was a huge step. This is likely to be true also in neuroscience.
The view for which McGinn is known is a jejune prediction, namely that science cannot ever solve the problem of how the brain produces consciousness. On what does he base his prediction? Flimsy stuff. First, he is pretty sure our brain is not up to the job. Why not? Try this: a blind man does not experience color, and he will not do so even when we explain the brain mechanisms of experiencing color. Added to which, McGinn says that he cannot begin to imagine what it is like to be a bat, or how conscious experience might be scientifically explained (his brain not being up to the job, as he insists). This cognitive inadequacy he deems to have universal epistemological significance.
Alongside the arrogance, here is one whopping flaw: no causal explanation for a phenomenon, such as color vision, should be expected to actually produce that phenomenon. Here is why: the neural pathways involved in visually experiencing color are not the same pathways as those involved in intellectually understanding the mechanisms for experiencing color. Roughly speaking, experiencing color depends on areas in the back of the brain (visual areas) and intellectual understanding of an explanation depends on areas in the front of the brain.
And from McGinn's reply:
Churchland’s account of my arguments for our cognitive limitations with respect to explaining consciousness bears little relation to what I have written in several books, as anyone who has dipped into those books will appreciate. What she refers to as a “whopping flaw” in my position (and that of many others) is simply a complete misreading of what has been argued: the point is not that having a causal explanation for a phenomenon should produce that phenomenon, so that a blind man will be made to see by having a good theory of vision. The point is rather that a blind man will not understand what color vision is merely by finding out about the brain mechanisms that underlie it, since he needs acquaintance with the color experiences themselves....
I can see nothing enlightening in this exchange.
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