Thursday 4/9

Consciousness V: Responses




Class Discussion

We will use zoom for class discussion, meeting at the same time as class, but online. Please download the client here for your computer, laptop, or smartphone. You do not need an account, nor do you need to pay for the service. I will text a meeting ID and meeting password to the class via our class GroupMe and via email about 15 minutes prior to class. We will also use the same zoom room for the dedicated office hour immediately following class.

Video Lecture

None for today. I think we covered it all in our class discussion reasonably well.


Today we set out to consider some of the responses to the various 'gaps' we've discovered which make it difficult, if not impossible, to see how phenomenal consciousness could emerge from purely physical processes. To be sure, there are many, many responses. Consider this synopsis an attempt to back-fill our meeting a bit.

Responses generally divide between Higher-Order Thought (HOT) theories and Representational theories. HOT theories attempt to describe how purely neurological processes can, by attending to other neurological processes, give rise to phenomenal consciousness. Representational theories note the representational role of qualia and attempt a conceptual reduction of qualitative experience to the cognitive process of representing states of affairs.

Thus, representational theories attempt to eliminate the problem of phenomenal consciousness by a kind of conceptual reduction, while HOT theories attempt to eliminate it via a neurological reduction. The responses to either approach have not been more than tepid, however.

Churchland sets out to counter all such arguments by arguing that the conceivability of having pains without the physical states the physicalist assures us they must be will eventually disappear when we do have a (more) complete science of psychology. His argument is by analogy to the property of electromagnetic waves and their capacity to illuminate or special property of luminosity. So imagining a pain with a physical state is just like imagining a dark universe rich in electromagnetic waves, which we cannot do.

Churchland invites us to give psychology a rain check it may not deserve. Nevertheless, it is intriguing to think that perhaps our intuitions are simply mistaken when it comes to the Knowledge, Model, and Explanatory Gaps.

Continuing our discussion of possible responses to the hard problem of phenomenal consciousness today, we next considered mysterianism, or the view that although there is a physical explanation for phenomenal consciousness, it is not an explanation we can understand because we are cognitively closed to it. I got more than a few puzzled looks at the proposition that physicalism is true even though the gaps cannot be bridged, so let me see if I can explain it better here.

Following McGinn*, assume physicalism and let P be the property of the brain causally responsible for phenomenal consciousness. Reflecting on P, McGinn concludes that we are driven to mysterianism, or the thesis that we cannot solve the hard problem of phenomenal consciousness because we suffer cognitive closure with respect to P. That is, our conceptual resources are limited in such a way that we are necessarily blind to P even though P is the very property making possible our own phenomenal consciousness. Being essentially blind to P, we cannot provide a theory of the physical basis of phenomenal states. Absent a theory of the physical basis of phenomenal states, the natural explanation solving the hard problem of phenomenal consciousness--in spite of its existence--is necessarily inaccessible.

Our continuing failure thus far to provide such an explanation at least raises the specter that we are cognitively closed to P. That the failures have been abjectly dismal (and the problem hard in such a way that we cannot even envision how conceptual or empirical investigation might solve it) solidifies the specter of cognitive closure enough to make it worrisome for optimists. McGinn, however, goes further than observing our puzzling lack of progress and gives an argument for cognitive closure.

Briefly, the facts of phenomenal consciousness are available by introspection alone, while the facts of brain states are available by sensory perception alone. That is, we cannot introspectively grasp brain states any more than we can perceive phenomenal states by our senses. Thus P escapes us working from the top down since no amount of introspection can reveal the brain states constituting P, yet no property working from the bottom up can be identified as a candidate P by brain scans since every mere brain property is spatially located and extended in sensory perception. The spatial properties attending sensory perception of brain states, however, make them not merely ill-suited to explaining phenomenal consciousness: The spatial nature of sense perception is incompatible with explaining consciousness. Thus, to paraphrase McGinn, phenomenal consciousness is fully noumenal with respect to brain studies. New and improved brain scans offer no hope of breaching the gap between the noumenal explanandum, phenomenal consciousness, and the explanans, P.

We are cognitively closed to P inasmuch as P is neither introspectively available nor identifiable in sensory perception, yet we are cognitively confined to introspection and sensory perception. For us, the natural explanation of phenomenal consciousness occupies an epistemic occlusion. Lacking the right sort of conceptual resources, phenomenal consciousness is thus essentially mysterious to creatures like us. Our inclination to invoke supernatural explanations (souls) or at least lavishly enrich natural resources (epiphenomenalism or pan-psychism) is understandable if unjustifiable.

McGinn has been rightly criticized** for asserting that we can fully understand a problem while wholly lacking the capacity to grasp solutions to it, since understanding a problem seems to require at a minimum a conception of possible solutions. Nevertheless, in this paper I argue that cognitive closure with respect to the neural substrate of phenomenal consciousness is a necessary outcome of the complexity constraining the cognition of any creature whatsoever. That is, while computability theory shows that there are at most countably many computable functions despite there being uncountably many functions--the halting problem being a case in point--complexity theory demonstrates further limitations on computation that are too often ignored in developing computational theories of mind. For us, the brain is necessarily a black box (unavailable to introspection in just the way hands, feet, and eyes are not) as a result of the complexity problem posed by being conscious of the neural basis of conscious states. Introspection does not reveal P because it could not be consciously available, and it cannot be consciously available because being so would recursively exhaust any and all computational resources. The dubious possibility of hypercomputational beings notwithstanding, the crux of my argument is showing that temporal complexity constraints on computation epistemically occlude the solution of the problem of phenomenal consciousness from introspection. Complexity theory precludes top-down solutions, in short.

*McGinn, C. 1989, "Can We Solve the Mind-Body Problem?", in Mind 98: 349-66.

**Kriegel, U. 2003, "The New Mysterianism and the Thesis of Cognitive Closure" in Acta Analytica, 18: 177-91.

***McGinn, C. 1995, "Consciousness and Space", in Journal of Consciousness Studies 2: 220-30.