This is an addendum to Thomas Nagel on the Mind-Body Problem. In that entry I set forth a problem in the philosophy of mind, pouring it into the mold of an aporetic triad:
1) Conscious experience is not an illusion.
2) Conscious experience has an essentially subjective character that purely physical processes do not share.
3) The only acceptable explanation of conscious experience is in terms of physical properties alone.
Note first that the three propositions are collectively inconsistent: they cannot all be true. Any two limbs entail the negation of the remaining one. Note second that each limb exerts a strong pull on our acceptance. But we cannot accept them all because they are logically incompatible.
This is one hard nut to crack. So hard that many, following David Chalmers, call it, or something very much like it, the Hard Problem in the philosophy of mind. It is so hard that it drives some into the loony bin. I am thinking of Daniel Dennett and those who have the chutzpah to deny (1). But eliminativism about conscious experience is not worth discussing outside of the aforementioned bin.
Sophistry aside, we either reject (2) or we reject (3). Nagel and I accept (1) and (2) and reject (3). Those of a scientistic stripe accept (1) and (3) and reject (2).
What I didn't do in my original post was to state why a Nagel-type answer is better than a scientistic one.
Why not just reject (2)? One way to reject it is by holding that some physical processes are essentially subjective. Consider any felt sensation precisely as felt, a twinge of pain, say, or a rush of euphoria. Why couldn't that felt sensation be identical to a physical process transpiring in one's brain?
Here is an argument contra. Not every brain event is identical to a conscious experience. There is a lot going on in the brain that does not manifest itself at the level of consciousness. What then distinguishes those brain events that are conscious experiences from those that are not? There will have to be a difference in properties. But if the only properties are physical properties, taking 'physical' in a broad sense to include the properties mentioned in physics, chemistry, electro-chemistry, and so on, then there will be no way to distinguish between conscious and non-conscious brain events. Since there is that distinction, conscious experiences cannot be identical to brain events. (Don't forget: eliminativism has been eliminated.)
More simply, perhaps, the claim that a particular conscious experience is numerically identical to a brain event violates the Indiscernibility of Identicals. Necessarily, if x, y are identical (one and the same), then whatever is true of x is true of y and vice versa. Equivalently, if x = y, then x, y share all properties. (After all, if two putatively distinct items are in reality one item, then it is trivially the case that 'they' share all properties.) But conscious experiences and physical states do not share all properties. It could be true of a pain that it is bearable, excruciating, throbbing, non-throbbing, etc. But these phenomenal predicates cannot be true of a physical state such as brain state. Why not? Because physical states have only physical properties, and no phenomenal properties.
"But if the pain and the brain state are identical, then they must share all properties!" True, but which properties are those? The physicalist/materialist/naturalist can admit only physical properties. His aim is to reduce the mental (or at least the qualitatively mental) to the physical, but without eliminating the mental. That I claim is impossible. For again, conscious experiences are essentially subjective, as Nagel says, but there is nothing essentially subjective about physical states as physics and the related natural sciences conceive them. The materialist reduction doesn't work. Sensory qualia have not been show to be material in nature.
Going Mysterian
Someone who thinks that qualia just have to be material in nature might at this point go mysterian along the lines of Colin McGinn. The mysterian grants that we cannot understand how that twinge of pain or that sense of euphoria could be just a complex state of the brain, a pattern of neuron firings. But he insists that it is nevertheless the case. It is just that our cognitive architecture makes it impossible for us to understand how it could be the case. After all, if x is actual, then it is possible even if we cannot understand how it is possible. It is and will remain a sort of secular mystery.
In other words, the unintelligibility of the reduction of consciousness to matter is not taken as an argument against this reduction, but as an argument against our ability to grasp certain fundamental truths. Thus (2) and (3) above are both true and hence logically consistent; it is just that insight into this consistency is beyond our ken. What is unintelligible to us is intelligible in itself. In reality, my felt pain is identical to something going on intracranially; it is just that insight into how this is possible is impossible for us given how were are constructed.
There are problems with this mysterian way out that I may discuss in a separate post.
Two Ways of Referring to the Same Thing?
Another option for the materialist is to invoke the familiar idea that linguistic and epistemic access to one and the same item can be had in different ways, and that duality of linguistic and/or epistemic access need not be taken to argue ontological duality in that to which one gains access. Reference to one and the same item can be routed through different senses or modes of presentation. Different terms, with different senses, can be used to target one and the same referent. 'Morning Star' and 'Evening Star,' though differing in sense, can be used to refer to the same celestial body, the planet Venus.
Why not say something similar about the physical state I am in when I feel pain? Why not say that there are two ways of accessing the same physical state? The one mode of access is via neuroscience, the other is 'from the inside' via the pain's qualitative feel to the one who endures it. If so, there are not two states or events one physical and the other mental differing in mode of existence; there is exactly one state or event, and it is physical. Dualism is avoided. The upshot is that, contra Nagel, the third-person physicalistic approach to the mind does not leave anything out. One may go on to tax Nagel, Searle, and Co. with illicitly inferring a difference in mode of existence from a difference in mode of linguistic/epistemic access. Something like this objection is made by Christopher Peacocke in his review of Nagel's The View from Nowhere (Philosophical Review, January 1989.)
It's a nice try, a very nice try. And it is exactly what one would expect from someone who takes an objectifying third-person view. What's more, it would be in keeping with Occam's Razor if mind could be seamlessly integrated into nature. Unfortunately, the pain I am in is not a mode of presentation, or means of epistemic access, to the underlying brain state. Thus the Fregean analogy collapses. The sense of 'morning star' mediates my reference to Venus; but my pain quale, even if it is caused by the brain state, does not mediate my reference to it.
Let me see if I can make this clear. The suggestion is that the same physical reality appears, or can appear, in two different ways, a third-person way and a first-person way, and that this first-person way of access is no evidence of a first-person way of being. One problem is the one I just alluded to: there is no clear sense in which a pain quale is an appearance of a brain state. The former may be caused by the latter. But that is not to say that the pain quale is of the brain state. The felt pain does not present the brain state to me. It does not present anything (distinct from itself) to me. After all, the felt pain is a non-intentional state. No doubt it has a certain content, but not an intentional or representational content. One can describe it without describing what it is of, for the simple reason that there is nothing it is of. An intentional state, however, cannot be described without describing what it is of.
The Fregean sense/reference analogy therefore breaks down. The basic idea was that one and same reality can appear in different ways, and that the numerical difference of these ways is consistent with a unitary mode of existence of the reality. A felt pain, however, is not an appearance of a reality, but an appearance that is a reality. The appearing of a felt pain is its being, and its being is its appearing. And because this is so, the felt pain is a distinct reality from the brain state. Not only is it a distinct reality, it is a distinct reality with a distinct, irreducibly subjective, mode of existence.
Nagelus vindicatus est. There is something essentially incomplete about a third-person approach to reality. It leaves something out, and what it leaves out is precisely that which makes life worth living. For as Wilfrid Sellars once said to Daniel Dennett over a fine bottle of Chambertin, "But Dan, qualia are what make life worth living!" (Consciousness Explained, p. 383)
In vino veritas.
I conclude that if our aporetic triad has a solution, the solution is by rejecting (3).
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