On the Apparent Inconceivability of Borderline Cases of Consciousness

Let's call a state or process a borderline case of consciousness if it is in the indeterminate gray zone between being a conscious state or process and being a nonconscious state or process. Consider gastropods, for example. Is there something it's like to be a garden snail? Or is there nothing it's like? If borderline consciousness is possible then there's a possibility between those two: the possibility that there's kind of something it's like. Consider other vague predicates or properties, such as greenness and baldness. Between determinate baldness and determinate non-baldness is a gray zone of being kind of bald. Between determinate greenness and determinate non-greenness there's a range of kind of greenish shades, with no sharp, dichotomous boundary. Might consciousness be like that? Might some organisms in that in-betweenish zone?

For a human case, consider waking from anaesthesia or dreamless sleep. Before you wake you are (let's suppose) determinately nonconscious. At some point, you are determinately conscious, though maybe still feeling confused and hazy-minded, still getting your bearings. Must the transition between the nonconscious and the conscious state always be sharp? Or might there be some cases in which you are only kind of conscious, i.e., there's only kind of something it's like to be you?

We need to be careful about the concept of "consciousness" here. You might be only half-aroused and not fully coherent, responsible, or knowledgeable of your location in time and space. Such a confused state has a certain familiar phenomenal character. But that is not a borderline case of consciousness in the intended sense. If you are determinately having a stream of confused experience, then you are determinately conscious in the standard philosophical sense of "conscious". (For a fuller definition of "conscious", see here.). An in-between, borderline case would have to be a case in which it's neither quite right to say that you are having confused experiences nor quite right to say that you aren't.

It is commonly objected that borderline cases of consciousness are inconceivable. (Michael Antony and Jonathan Simon offer sophisticated versions of this objection.) We can imagine that there's something it's like to be a particular garden snail at a particular moment, or we can imagine that there's nothing it's like, but it seems impossible to imagine its kind of like being something. How might such an in-between state feel, for the snail? As soon as we try to answer that question, we seem forced either to say that it wouldn't feel like anything or to contemplate various types of conscious experiences the snail might have. We can imagine the snail's having some flow of experience, however limited, or we can imagine the snail to be an experiential blank. But we can't in the same way imagine some in-between state such that it's neither determinately the case that the snail has conscious experiences nor determinately the case that the snail lacks conscious experiences. The lights are, so to speak, either on or off, and even a dim light is a light.

Similarly, as soon as we try to imagine the transition between dreamless sleep and waking, we start to imagine waking experiences, or confused half-awake experiences, that is, experiences of some sort or other. We imagine that it's like nothing - nothing - nothing - something - something - something. Between nothing and something is no middle ground of half-something. A half-something is already a something. Borderline consciousness, it seems, must already be a kind of consciousness unless it is no consciousness at all.

I'm inclined to defend the existence of borderline consciousness. Yet I grant the intuitive appeal of the reasoning above. Before admitting the existence of borderline cases of consciousness, we want to know what such a borderline state would be like. We want a sense of it, a feel for it. We want to remember some borderline experiences of our own. Before accepting that a snail might be borderline conscious, neither determinately lights-on nor determinately lights-off, we want at least a speculative gesture toward the experiential character of such in-betweenish phenomenology.

Although I feel the pull of this way of thinking, it is a paradoxical demand. It's like the Catch-22 of needing to complete a form to prove that you're incompetent, the completing of which proves that you're competent. It's like demanding that the borderline shade of only-kind-of-green must match some sample of determinate green before you're willing to acept that it's a borderline shade that doesn't match any such sample. An implicit standard of conceivability drives the demand, which it is impossible to meet without self-contradiction.

The implicit standard appears to be this: Before granting the existence of borderline consciousness, we want to be able to imagine what it would be like to be in such a state. But of course there is not anything determinate it is like to be in such a state! The more we try to imagine what it would be like, the worse we miss our target. If you look through a filter that shows only determinately bald people, you won't see anyone who is borderline bald. But you shouldn't conclude that no borderline bald people exist. The fault is in the filter. The fault is in the imaginative demand.

In another sense, borderline cases of consciousness are perfectly conceivable. They're not like four-sided triangles. There's no self-contradiction in the very idea. If you're unhappy with your inability to imagine them, it could be just that you desire something that you can't reasonably expect to have. The proper response might be to shed the desire.

A philosophically inclinded middle-schooler, on their first introduction to imaginary numbers, might complain that they can't conceive of a number whose square is -1. What is this strange thing? It fits nowhere on the number line. You can't hold 3i pebbles. You can't count 3i sheep. So called "imaginary numbers" might seem to this middle-schooler to be only an empty game with no proper reference. And yet there is no contradiction in the mathematics. We can use imaginary numbers. We can even frame physical laws in terms of them, as in quantum mechanics. In a certain way, imaginary numbers are, despite their name, unimaginable. But the implicit criterion of imagination at work -- picturing 3i sheep, for example -- is inappropriate to the case.

We can conceive of borderline cases of consciousness, in a weaker sense, by forming a positive conception of clear cases of consciousness (such as regular waking consciousness and such as the experience of feeling disoriented after waking) and by imagining in a different way, not from the inside, cases in which consciousness is determinately absent (such as dreamless sleep), and then by gesturing toward the possibility of something between. There is, I think, good reason to suppose that there are such in-between, borderline states. Nature is rarely sharply discontinuous. On almost every theory of consciousness, the phenomena of consciousness are grounded in states of the brain that aren't sharp-boundaried. (I'm working on an article that defends this view at length, which I hope to have in circulating shape soon.) This is fairly abstract way of conceiving of such states, but it is a conception.

If borderline cases were common enough and important enough in human life, we might grow accustomed to the idea and even develop an ordinary language term for them. We might say, "ah yes, one of those jizzy states, in the intermediate zone betweeen consciousness and nonconsciousness." But we have no need for such a concept in everyday life. We care little about and needn't track borderline cases. We can afford to be loose in talking about gradual awakenings. Similarly for nonhuman animals. For everyday purposes, we can adequately enough imagine them either as determinately conscious or as nonconscious machines. There has never been a serious linguistic pressure toward an accurate heterophenomenology of nonhuman animals, much less a heterophenomenology with a dedicated label for in-between conditions.

Thus, if we accept the existence of borderline cases of consciousness on general theoretical grounds, as I'm inclined to think we should, we will need to reconcile ourselves with a certain sort of dissatisfaction. It's incoherent to attempt to imagine, in any determinate way, what it would be like to be in such a state, since there's nothing determinate it would be like. So first-person imaginative transportation and phenomenological memory won't give us a good handle on the idea. Nor do we have a well-developed science of consciousness to explain them or an ordinary folk concept of them that can make us comfortable with their existence through repeated use.

It's understandable to want more. But from the fact that I cannot seize the culprit and display their physiognomy, it does not follow that the jewels were stolen by no one.

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