I have been reading fairly extensively in the literature on consciousness.  Stuff written over the past thirty years by philosophers and neuro-biologists.  This post simply aims to get down a few specifics about what consciousness is.

This post is derived from two sources: Nicholas Humphrey, Sentience: The Invention of Consciousness (MIT Press, 2023) and Walter Veit, A Philosophy for the Science of Animal Consciousness (Routledge, 2023).  Both Humphrey and Veit are Darwinians who aim to give an account of how consciousness emerged in the course of evolutionary history.  I may take up their Darwinism (which is problematic in my eyes) in a later post.  For now I just want to get to how they describe consciousness, since I think they are both admirably clear on that issue and basically convincing.  I don’t presume to assess whether they are right.  Neither of them (and as far as my reading goes no one else in the world either) has a slam dunk physiological/neurochemical account of consciousness.  Instead, they both rely on a phenomenological description (what consciousness feels like and is experienced as) and a functional description (what consciousness does).

Let’s start with Veit.  He offers five fundamental functions for consciousness:

1) sensory experience.  Consciousness entails being able to process various stimuli that originate outside the organism as well as internal stimuli (such as the sensation of hunger);

2) evaluative. Consciousness provides the ability of an organism to evaluate its environment and react accordingly.  That is, the organism does not just receive sensory signals, but also evaluates them.

3) the integration of experiences in the present moment.  Consciousness unifies; it takes incoming signals that might be visual, auditory, scents etc. and organizes them into an holistic understanding of the present, of what is before the organism and how its various components stand in relation to one another. 

4) the integration of experience across time.  Consciousness also unifies across time, weaving together the various experiences at specific moments into a history (or narrative) that specifies the relations between the particulars of individual experiences.  (I find this function dubious.  Or, better, I would not make such an easy assumption of unity, even if the effort to unify does exist.  However, it also seems to me that efforts to unify are also more than happy to dismiss various experiences as irrelevant within certain narrative frames.  So, yes, we deploy narratives to organize experiences over time, but I don’t think of the narratives as holistic in the sense of incorporating everything.  Lots of stuff doesn’t fit with lots of other stuff, even as some things do go together.)

5) Self-consciousness.  This, of course, is the biggie, the holy grail of consciousness studies.  How to explain its existence—either by specifying its function in a Darwinian account or by providing a bio-chemical account of its existence.  It is a matter of faith for just about everyone writing about consciousness that there is a material, bio-chemical cause of consciousness. Materialism (no non-material facts or substances; thus consciousness must be a material thing) and naturalism (everything that exists does so–and originates–within a natural frame; nothing extraneous to nature) are the default positions for 95% of contemporary philosophers and scientists. But no one has come particularly close to providing such a materialistic account of consciousness, so that a skeptic like Colin McGinn argues that no such account is likely to be given within (to pick an arbitrary number) the next 100 years.  Materialism, in other words, is an unproved axiom, an item of faith that gets the whole game rolling.

Humphrey is good at describing self-consciousness.  He zeroes in on “sensations” and “qualia.”  He writes:  “Sensations are basically mental states . . . that track what’s happening at our sense organs.. . . They provide us, as subjects, with information about the quality of the sensory stimulus, its distribution and intensity, its bodily location, and–especially—how we evaluate it: the pain is in my toe and horrible; the red light is at my eyes and stirs me up. But ‘tracking’ this information is only half the story.  For, as we can each of us attest, sensations have a qualitative dimension that sets them apart from all other mental states and attitudes.  There’s something that our pains, smells, sights, and so on have in common that our thoughts, beliefs, wishes and so on don’t”(2).  That something extra is what Humphrey (following common philosophical usage) calls “qualia.”  Sights and smells have a bodily dimension that beliefs and wishes seem to lack. (I think this statement wrong, as I will discuss below.) Consciousness for Humphrey is tied to the ability to track, to register, the “feel” of sensations, to not only see the Van Gogh painting, but to register the sensation that accompanies seeing it. 

Qualia, then, refers to the “phenomenal quality” of sensations. (page 3).  Which leads Humphrey (for a variety of reasons that are generated by empirical studies of things like “blind sight”) to distinguish between “cognitive consciousness” and “phenomenal consciousness.”  There is plenty of evidence that most organisms can process and then respond to information provided by their senses.  But for Humphrey at least there is not evidence that starfish have any consciousness of the “feel” of perceptual experience even as they do respond to sensory input.  For biological reasons, he thinks phenomenal consciousness is only available to warm-blooded animals. 

He tells us that “consciousness of the kind we are talking about” is present when “sensations [are] represented as having phenomenal properties” (139).

Here’s Humphries three stages of consciousness; he thinks they are evolutionary stages even as there are also organisms in 2023 who are living examples of each stage.  “(a) First came sentition—an evaluative motor response to sensory stimulation. 9b) Then came sensation, when animals discovered how to monitor this response so as to arrive at a mental representation of what the stimulations means to them. [Cognitive consciousness.] (c) Then, once the process was privatized and feedback loops established, came phenomenal sensation, with the representation taking on a whole new look” (146).

He elaborates: stage one includes “animals with elementary uncentralized nervous systems, whose behavior is largely reflex and does not involve creative processing of information: for example, sea anemones, starfish, earthworms, slugs” (146).

Stage two are the “’Sub-Sentients.’ They do form mental representations of sensory stimulation and what it means but their sensations lack a phenomenal dimension.  I would expect this group to include animals with developed brains that may be capable of intelligent behavior that requires cognitive consciousness.  . . . They will, however, have a limited sense of themselves as individuals and will not attribute selfhood or mental states to others; for example, honeybees, octopuses, goldfish, frogs” (147).

Finally, at stage three, we get the “true ‘Sentients.’  They uniquely represent what’s happening at their sense organs as having phenomenal depth.  . . . They will be highly intelligent, especially in the social sphere, and have a strong sense of their own individual selfhood; for example: dogs, chimpanzees. parrots, humans” (147).

Note that Humphrey thinks “privatization” is a crucial step toward full phenomenal consciousness. There must be the sense of my sensation and its “feel” as belonging to me.  It’s my pain, not yours.  But, of course, we can say the same about my thoughts, beliefs, wishes, and desires.  It seems odd to claim wishes and beliefs don’t have a “feel” attached to them.  Surely, there is a sensation that has a phenomenal quality attached to it when I feel jealous or in love or believe in my country right or wrong.  And even though it is difficult, we like to think that evaluation (and subsequent revision) of our beliefs and desires is possible, just as we evaluate (and sometimes revise) what we take to be sensory information. 

Humphrey, with his privatization thesis, is strongly committed to self-consciousness. Many of those who write about consciousness take the more Humean position that the “self” is, at the very least, problematic.  There is no underlying substance or thing to the temporal flow of sensations, of experience.  But Humphrey appears to believe that you can’t have phenomenal awareness unless there is a self to whom the sensations that are registered belongs.  I think it fair to say, although he never explicitly says this, that his position is that there is no phenomenal consciousness without selfhood.  Phenomenal consciousness is a necessary condition of selfhood (as I understand his work). Maybe better to say that phenomenal consciousness creates selfhood. Where phenomenal consciousness is, the self will also be. No phenomenal consciousness without a self accompanying it. Pushing back a bit from the entanglement of phenomenal consciousness with selfhood, all kinds of environmental and biological things have to be in place for phenomenal consciousness to emerge in evolutionary history and to be present in organisms today.    That’s Humphrey’s position.

Veit would seem equally committed to a fairly robust notion of the self.  Once he assigns consciousness the task of unifying experiences across time, he is flying in the face of Humean atomism.  And, of course, Veit accepts without much discussion the basic idea of “self-consciousness.”  This is Nagel’s famous “what it feels like to be a bat.”  We don’t only have a sensation related to eating a taco; we also have a sensation related to being one’s self.  My selfhood has a “feel” to it—and the ability to register and reflect on that “feel” is part of what it is to be conscious.  Consciousness is of the self as well as of things that exist outside of and apart from my body. 

I am just reporting here.  I don’t have enough footing in this whole field to even know what I think is true and what I think dubious.  Veit’s five-fold list of functions seems useful to me just because it puts some flesh on the bones, at least points us to some of the capabilities we would be talking about when we appeal to consciousness.  And Humphrey’s focus on qualia, on the phenomenal, usefully specifies the on-the-ground experience that undergirds the assertion that consciousness exists in the face of skeptics who think it does not.  (Hume may have been skeptical about the self; but he was not skeptical about consciousness; his very distinction between “impressions” and “ideas” presupposes consciousness as the faculty that works upon the “impressions” offered by the encounter with the world.)

One final point for now.  Bentham said the only relevant question to ask when developing a hierarchy of beings, from the “lowest” forms to the “higher”, was whether a given being could suffer.  All the rest was sophistry in his view.  Our relation to other entities should be governed by their ability to suffer.  We can do whatever we want to stones because they are insensate. But if clams and goldfish experience pain as something akin to the unpleasant experience we call pain, then we have as absolute an obligation to avoid inflicting pain on them as we do on a two year old human.  Nothing in Humphrey’s distinction between stage two and stage three animals suggests that stage two animals are incapable of suffering.  The stage one case is a bit more ambiguous; I don’t know what he would say about earthworms and pain. 

• Consciousness