Our brains are made of matter: neurons, biochemicals and other physical stuff. All these things are (as it were) “flesh and blood”. So, the British philosopher Colin McGinn (1950-) asks, how can “technicolour phenomenology arise from [this] soggy grey matter?”. In other words, why does the brain produce, cause or give rise to something so different from matter itself? What makes the brain so different to all the other human organs? More specifically, what is it, exactly, about billions of neurons that gives rise to consciousness or experience?
These questions were asked (if not in these precise ways) in Colin McGinn’s well-known and important paper, ‘Can We Solve the Mind-Body Problem’. That paper was published in 1989 in the journal Mind.
Mind and Brain
Despite all the above, the main issue of McGinn’s paper is not one of how or why consciousness arises from the the brain. It raises the possibility that the link between the brain and the mind (or, more accurately, consciousness/experience) may be — permanently? — closed off to us.
McGinn calls this “cognitive closure”. And the “property” responsible for that cognitive closure he names P.
McGinn focuses on our (possible) cognitive limitations.
But firstly let’s take different species of animals. McGinn tells us that they are
“capable of perceiving different properties of the world and no species can perceive every property things may instantiate”.
Think here of bats and echolocation. Dogs too can hear sounds which we can’t even register and they have a far better sense of smell than human beings. So what’s true for other animal species will also be true for human beings.
Yet all these examples only display sensory — i.e., not cognitive — limitations and extensions.
So let’s get back to cognitive closure.
McGinn’s (or our) P is a real (or actual) property. It may even be concrete (e.g., part of the brain). Thus McGinn doesn’t believe that he’s (to use his own term) “irrealist” about P. That said, McGinn does cite the possibility that P is noumenal. As with Kant, noumena are permanently unknowable — by (Kantian) definition. (Kant also believed — living before Darwin - that the structures of the mind-brain would remain static for… well, the rest of time.)
It’s the very nature of the mind-brain link which renders P permanently closed off to us. Yet despite that possibility, P could still be — at least according to McGinn — part of a respectable naturalistic theory. Again, we shouldn’t be irrealist or mysterious about P. (Many philosophers do see Colin McGinn as a mysterian.) That said, one can’t help but see x as being mysterious if that x is also believed to be permanently closed off to us.
So does McGinn actually think in terms of permanent cognitive closure?
Hume, Locke and Kant
McGinn discusses another case of closure which occurred in the philosophy of David Hume (1711–1776).
To Hume, our perceptual limitations determine our cognitive limitations. (Hume was a thoroughgoing empiricist.) More clearly, Hume believed that because our “ideas” are always copies of sensory “impressions”, then that also meant that our concept-forming system itself must always rely on— in whichever ways — those impressions. Thus nothing can transcend the information provided by impressions. (It can be asked here what was Hume’s philosophical position — as an empiricist — on such things as the existence of distant stars, the past, other minds, mathematics, etc.)
Now for Locke.
According to McGinn, the English philosopher John Locke (1632–1704) also believed that “our ideas of matter are quite sharply constrained by our perceptions”. To Locke, this also meant that (to use McGinn’s words) “the true science of matter is eternally beyond us”. Mind-free matter is a (to use Locke’s own well-known phrase) “something-I-know-not-what”. In concrete and specific terms, this means (or in the 17th century it meant) that we can never know what, say, solidity “ultimately is”. (Why does McGinn feel the need to use the word “ultimately”?) Again, this doesn’t mean that Locke believed that nature “is itself inherently mysterious”. (It can be asked how McGinn knows that Locke didn’t think this.) According to McGinn’s Locke, the mystery simply
“comes from our own cognitive limitations, not from any objective eeriness in the world”.
Kant, on the other hand, believed that knowledge begins with impressions (or, more accurately, with “phenomena”). However, he also believed that impressions aren’t the sole source of our knowledge. That’s primarily because Kant postulated innate a priori concepts and categories which (as it were) get to work on phenomena.
Back to McGinn
Colin McGinn explicitly states his position with regards to P. To repeat: he claims to resolutely shuns what he calls “the supernatural”. P must be “natural”. (How does he know this?) He goes on to say that
“it must be in virtue of some natural property of the brain that organisms are conscious”.
McGinn then concludes:
“There just has to be some explanation for how brains subserves minds.”
Again, why must P be natural? Is this a case of McGinn having (as it were) faith in naturalism? Alternatively, is McGinn’s theory of P naturalist in the first place?
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