An interesting blog post by William Lycan gives a brisk treatment of the interesting question of whether consciousness comes in degrees, or is the kind of thing you either have or don’t. In essence, Lycan thinks the answer depends on what type of consciousness you’re thinking of. He distinguishes three: basic perceptual consciousness, ‘state consciousness’ where we are aware of our own mental state, and phenomenal consciousness. In passing, he raises interesting questions about perceptual consciousness. We can assume that animals, broadly speaking, probably have perceptual, but not state consciousness, which seems primarily if not exclusively a human matter. So what about pain? If an animal is in pain, but doesn’t know it is in pain, does that pain still matter?

Leaving that one aside as an exercise for the reader, Lycan’s answer on degrees is that the first two varieties of consciousness do indeed come in degrees, while the third, phenomenal consciousness, does not. Lycan gives a good ultra-brief summary of the state of play on phenomenal consciousness. Some just deny it (that represents a ‘desperate lunge’ in Lycan’s view); some, finding it undeniable, lunge the other way – or perhaps fall back? – by deciding that materialism is inadequate and that our metaphysics must accommodate irreducibly mental entities. In the middle are all the people who offer some partial or complete explanation of phenomenal consciousness. The leading view, according to Lycan, is something like his own interesting proposal that our introspective categorisation of experience cannot be translated into ordinary language; it’s the untranslatability that gives the appearance of ineffability. There is a fourth position out there beyond the reach of even the most reckless lunge, which is panpsychism; Lycan says he would need stronger arguments for that than he has yet seen.

Getting back to the original question, why does Lycan think the answer is, as it were, ‘yes, yes, no’? In the case of perceptual consciousness, he observes that different animals perceive different quantities of information and make greater or lesser numbers of distinctions. In that sense, at least, it seems hard to argue against consciousness occurring in degrees. He also thinks animals with more senses will have higher degrees of perceptual consciousness. He must, I suppose be thinking here of the animal’s overall, global state of consciousness, though I took the question to be about, for example, perception of a single light, in which case the number of senses is irrelevant (though I think the basic answer remains correct).

On state consciousness, Lycan argues that our perception of our mental states can be dim, vivid, or otherwise varied in degree. There’s variation in actual intensity of the state, but what he’s mainly thinking of is the degree of attention we give it. That’s surely true, but it opens up a couple of cans of worms. For one thing, Lycan has already argued that perceptual states come in degrees by virtue of the amount of information they embody; now state consciousness which is consciousness of a perceptual state can also vary in degree because of the level of attention paid to the perceptual state. That in itself is not a problem, but to me it implies that the variability of state consciousness is really at least a two-dimensional matter. The second question is, if we can invoke attention when it comes to state consciousness, should we not also be invoking it in the case of perceptual consciousness? We can surely pay different degrees of attention to our perceptual inputs. More generally, aren’t there other ways in which consciousness can come in degrees? What about, for example, an epistemic criterion, ie how certain we feel about what we perceive? What about the complexity of the percept, or of our conscious response?

Coming to phenomenal consciousness, the brevity of the piece leaves me less clear about why Lycan thinks it alone fails to come in degrees. He asserts that wherever there is some degree of awareness of one’s own mental state, there is something it’s like for the subject to experience that state. But that’s not enough; it shows that you can have no phenomenal consciousness or some, but not that there’s no way the ‘some’ can vary in degree. Maybe sometimes there are two things it’s like? Lycan argued that perceptual consciousness comes in degrees according to the quantity of information; he didn’t argue that we can have some information or none, and that therefore perceptual consciousness is not a matter of degree. He didn’t simply say that wherever there is some quantity of perceptual information, there is perceptual consciousness.

It is unfortunately very difficult to talk about phenomenal experience. Typically, in fact, we address it through a sort of informal twinning. We speak of red quale, though the red part is really the objective bit that can be explained by science. It seems to me a natural prima facie assumption that phenomenal experience must ‘inherit’ the variability of its objective counterparts. Lycan might say that, even if that were true, it isn’t what we’re really talking about. But I remain to be convinced that phenomenal experience cannot be categorised by degree according to some criteria.