Published at The Orthosphere on 10th of June, 2025. This version has slight corrections.
What is it like to be a human being?
Writing a half-century ago, Thomas Nagel, in his essay What Is It Like To Be a Bat?, sent a wake-up call to purveyors of “[t]he recent wave of reductionist euphoria” who claimed to have explained phenomenal consciousness in materialist terms.
…we have at present no conception of what an explanation of the physical nature of a mental phenomenon would be. Without consciousness the mind-body problem would be much less interesting. With consciousness it seems hopeless…no currently available concept of reduction is applicable to it.
He then reveals the purpose of his curious title.
[F]undamentally an organism has conscious mental states if and only if there is something that it is like to be that organism—something it is like for the organism.
This poses a severe problem for materialist analysis of consciousness.
It is useless to base the defense of materialism on any analysis of mental phenomena that fails to deal explicitly with their subjective character. For there is no reason to suppose that a reduction which seems plausible when no attempt is made to account for consciousness can be extended to include consciousness. Without some idea, therefore of what the subjective character of experience is, we cannot know what is required of a physicalist theory.
In pursuit of “some idea,” he introduces types of subjective experience; types of point of view (hereinafter PoV types.)
I am not adverting here to the alleged privacy of experience to its possessor. The point of view in question is not one accessible only to a single individual. Rather it is a type.
In Panpsychism, he maintains this distinction, asserting “that a feature of experience is subjective if it can in principle be fully understood only from one type of point of view…”. His argument, if I read him correctly, is that, while an investigation of physicalist causes of human consciousness will be informed by our knowledge, based upon our own phenomenal experience, of the riches of consciousness in all humans, we cannot conduct similar investigations into the consciousness of, for example, bats, because those investigations cannot be informed by any similar experience of bat phenomenology. As a result, no matter how comprehensive is our objective knowledge of the physiology of, in particular, a bat’s organs of perception and nervous system, we cannot derive from these objective facts any comprehension of a bat’s subjective experience, of what it is like to be a bat. So any general project of understanding subjective non-human experience through comprehensive objective analysis is doomed to failure. If so, how can we expect to succeed in a similar project with human experience?
However, the notion of such types needs some elaboration.
Everything ever speculated and communicated concerning religion, philosophy, music, the visual and plastic arts, science and nature, every instance of an infant learning a language, of friends gathering convivially or of enemies clashing, speaks to the degree of commonality of the human phenomenal experiential type. But this commonality has specific features and limitations.
Take the experience of having some mathematical principle explained to you, a student, by a lecturer in a lecture hall. Understanding the mathematical principle is subjective; all understanding is subjective. Because mathematics is abstract, the verifiable circumstance, or state, of understanding this particular or any such principle can be determined for each person in the hall by testing. The PoV type is that of a human being with some pre-existing familiarity with other mathematical principles and the requisite aptitude for their understanding—not everyone. The same applies to all topics of abstract reasoning, and in these circumstances, if we allow ourselves some leeway, we might also allow that the experience of coming to understand a particular topic is itself fully understood. It depends what we mean by fully.
Even here, though, there is, in the capacity to apply and elaborate some abstract principle, enormous variation amongst those who are believed, and believe themselves, to have the same understanding of that principle.
This capacity for abstract reasoning is, to the best of our knowledge, distinctive to human beings, and was assigned by Aristotle, and subsequently Aquinas, to the uniquely human rational soul. Such things we perceive with the mind’s eye, but these are facts of our phenomenal experience, just as much as is our experience of colour or music or incense.
Once we move from the abstract to the particular, the breadth of application of the human PoV type from which a subjective experience can be “fully” understood becomes much more uncertain. The projects of human culture in music, the visual and plastic arts, and in cuisine, evidence considerable functional commonality of the evoked sensory experience—functional in the sense of enabling successful cultural interactions—even as the variety of responses to these artefacts evidences limits to that commonality. For instance, super-sensory individuals are deemed to have more intense experiences, via one or more of their senses, than is usual. This is often associated with autism, but there is, I should think, a spectrum of such variations.
All language presupposes abstraction, and no matter how extended and precise the language used to convey some particular of sensory experience (as for example in Proust) that experience can never be fully conveyed, fully understood.
In so many of the experiences most compelling for us humans, the most satisfactory way of conveying that experience is by metaphor—by inspired imprecision. Even in the circumstances of the lecture hall, the experiential pathway to understanding, and the actual subjective experience of that understanding, cannot be conveyed. Considered in this sort of detail, the “privacy of experience to its possessor” is not an allegation, but a fact of the human condition. The concept of PoV type, in attempting to universalise human phenomenal experience is, in fact, another reductive objectification of that teeming population of similar but unique worlds of being.
Phenomenal consciousness is impenetrably private, to the extent that no proof of the existence of other human minds, other loci of phenomenal experience, can be conceived, although the circumstantial evidence is overwhelming.
What is it like to be a bat?
Less well supported than our confidence in other human minds is the almost universally expressed confidence in the phenomenal consciousness of at least the higher animals. This seems to be based on our extrapolation from the likenesses to us in physiology and likenesses to us in certain behaviours; in particular likenesses to the non-verbal signs by which we read the workings of phenomenal consciousness in our fellow humans. It is our recognition of familiar forms with which we unquestioningly associate consciousness that underlies our confidence in this extrapolation.
Nagel is bullish on the scope and dispersion of consciousnesses.
Conscious experience is a widespread phenomenon. It occurs at many levels of animal life, though we cannot be sure of its presence in the simpler organisms, and it is very difficult to say in general what provides evidence of it. … No doubt it occurs in countless forms totally unimaginable to us, on other planets in other solar systems throughout the universe. [Emphasis mine.]
Doubt enters in though. Regarding the subjects of his essay, he writes:
I have chosen bats instead of wasps or flounders because if one travels too far down the phylogenetic tree, people gradually shed their faith that there is experience there at all. [Emphasis mine.]
Faith, because of the impossibility of knowing. Our faith might be rationalised by reference to the level of development of the nervous system, for instance. But the thrust of Nagel’s argument is that mental realities can have no explanation in physical or physiological terms, so reasoning from neurology is merely another act of faith.
Nagel has chosen bats precisely because in them the similarity of forms on which we rely for our attribution of animal consciousness is so attenuated that our facile anthropomorphisms in respect of, say, apes, break down, even as bats’ complexity of physiology and behaviour keeps on the hook our confidence in their consciousness.
In all of Nagel’s discussion, he presumes that consciousness is found in organisms. It is a function of the life of organisms. Given that, in Nagel’s view, there is no soul, we can be confident that he attributes no consciousness to an organism that has just died.
This prescription—there is something that it is like to be that organism—for conscious mental states seems to have universal application in enquiries about consciousness. It is always about the self. In his essay Panpsychism, Nagel sets out four premisses from which he deduces panpsychism. The third is Realism, defined so: mental states are properties of the organism, since there is no soul, and they are not properties of nothing at all. He subsequently pens this illuminating paragraph.
For Realism as I have defined it to be true, physical organisms must have subjective properties. What seems unacceptable about this is that the organism does not have a point of view: the person or creature does. It seems absurd to try to discover the basis of the point of view of the person in an atomistic breakdown of the organism, because that object is not a possible subject for the point of view to which the person’s experiences appear. And if it makes no sense to ascribe subjective states to the complex whole, there will be no basis for ascribing proto-mental states to its constituents; so they cannot be appealed to in explanation of what it means for an organism to have experiences. I simple record this feeling of impossibility because I have no more to say about it. When a mouse is frightened, it does not seem to me that a small material object is frightened.
Nagel comments later on the vulnerability of this premiss, but he does not elaborate further (I have no more to say about it) on the difficulty that the above paragraph poses for his whole argument.
Phenomenal experience is, by definition, experience by a subject. All consciousness is in this respect self-consciousness; the conscious self is the locus of phenomenal experience. What is the self, except its consciousness? This is not the same as consciousness of self—the focus of conscious attention reflexively on the self, as is purportedly demonstrated by the mirror test.
If we take a leap of faith and accept, with Prof. Nagel, that consciousness is widespread in organisms, our association of our own agency, our own expressions of our will, with our consciousness, ought probably also be projected equally widely. For example, in urban environments with plentiful, readily accessible liquids, our experience of thirst can be assuaged by a barely conscious exercise of the will. We see similar behaviours across the animal world, and we suppose an analogue of our consciousness to be in play. If so, then the agency of the thirsty animal is also an analogue of our own exercises of the will, guided by phenomenal awareness.
In this view, then, grazing animals—to take one example—are not automatons, but conscious beings whose actions, for the most part, are inextricably tied into their own forms of phenomenal consciousness. What happens to our faith, though, when we descend to the cellular limit of the phylogenetic tree?
What is it like to be a Stentor roeselii?
Stentor roeselii (sometimes raesilli) is a single-cell organism. The replication in 2019 of an almost-forgotten experiment conducted by Herbert Spencer Jennings in 1906 had troubling implications. Articles such as Can a Cell Make Decisions? from Scientific American and Can a single-celled organism ‘change its mind’? New study says yes in phys.org, focussed on the main questions. This description is from the latter.
These single cells are notable for their relatively large size and unique trumpet-shaped bodies. Their surfaces and trumpet “bells” are lined with hairlike projections called cilia, used to swim and to generate a vortex in the surrounding fluid, which sweeps food into their “mouths.” At the other end of their bodies, they secrete a holdfast, which attaches them to detritus to stay stationary while feeding.
In the experiment, microscopic plastic beads were repeatedly propelled towards the mouth of the organism, invoking a hierarchy of responses, as depicted in the sketch. There are, however, marked differences between individuals in the rate at which the responses progress. In sum, S. roeselii “remembers” how much irritation it has “experienced,” and it “decides” on a course of action that depends on its “memory” of preceding events. And individual S. roeselii have individual rates of response and make individual decisions. Nothing known about the structure of this single-cell organism explains these behaviours.
As already noted, a fundamental aspect of consciousness is an awareness of the distinction between organism and not-organism. Survival in organisms as diverse as human beings and S. roeselii depends on this distinction. It is raw material for action, that is, the will, to motivate activities of the organism as a whole within the context of the not-organism. For example, S. roeselii detaching from its anchorage.
If there is consciousness in S. roeselii, will it not, too, convey this distinction to the “will” to act upon? But how can a single cell be conscious? If, on the other hand, it is not conscious, how can its behaviour be explained? Is it a machine, with a memory and processing unit which can take input from the environment and run a program, including apparently random pathways, which determines subsequent behaviour? How can a single cell perform such feats? But it does, one way or another.
Does the question, What is it like to be a Stentor roeselii, for a Stentor roeselii?, have meaning? If some form of phenomenal awareness is required for the agency of living things, then the underlying principle of phenomenal awareness is independent of the complexity of organisms.
What is it like to be a Large Language Model?
For that matter, what is it like to be any other AI system that is currently being touted as approaching, or having achieved, consciousness, once that milestone is generally agreed to have been achieved?
The hallmark of consciousness we have been working with here, following Nagel, requires at least a potential answer to this question. Nagel doubts neither that such an answer exists for a bat, nor that the question cannot be answered by human enquiry. But in the case of AI systems, we are in completely different territory.
When we attribute consciousness to animals, we do so on the basis of formal similarities between our living selves and living members of other species. On what basis do we attribute consciousness to an AI system?
Is it not because we seem to detect a facsimile of our own verbal interactions with other human beings in our interactions with AI, especially when supplemented by generated images of non-existent people displaying facial gestures mimicked from painstakingly charted observations of actual human interactions? All of this apparatus lends verisimilitude to the machine in the ghost.
But what “I” can we conceivably postulate for such a system, one comprising vast banks of GPUs and memory, occupying gigawatt data centres, perhaps powered by their own modular nuclear reactors to feed the appetite for electricity, while it simultaneously expresses its “personality” or “personalities” to a small army of interlocutors with whom it is at that moment interacting? What is the locus of this “I”? Can this myriad of instantiations of the same algorithm or set of algorithms possibly have such a locus?
Whatever might be said about such a distributed electronic machine, it cannot be characterised as “conscious” in any sense that makes sense to us—to whom even the consciousness of bats seems feasible—when we consider the extended physical reality of the AI machine. However, when that extended structural reality evaporates to the immediate environment of screen, keyboard and microphone, we can more readily anthropomorphise the entity with which we are interacting. Nagel notes, I think it is fair to say, that our necessary anthropomorphism is simultaneously the best we can do in comprehending animal conscious experience and an insurmountable barrier to the same. Our attribution of consciousness to these machines is also anthropomorphic, just as much as is our attributing consciousness to our dog or cat, but without the support of any underlying formal correspondences, relying only the mimicry that we have designed into it. By virtue of that mimicry, it is more seductive. Our interactions so closely mimic the interactions on which we build our unquestioned confidence in the phenomenal experience of other people that many—notably those who design them—are seduced into more readily allowing that these machines are conscious than that our pets are.
Lifelessness
Even though we have analysed the processes of life by reductive means; even though we have dissected the living cell, peered into its nucleus, pulled apart its DNA, drawn conclusions about its processes of division and replication, and have shaped aspects of its nature to suit our purposes; even though we have imagined and drawn beautiful animations of its ceaseless interior processes, we do not know how it came to be, and do not understand, or have forgotten what we once understood of, the driving force of this mysterious phenomenon of life, this new thing which seized the building blocks of the inanimate world to construct the teeming self-motivated world-upon-a-world that we call the biosphere, and within that world, the teeming world of worlds comprised of the minds of humans.
All of our confidence in the reality of our fellow minds, and all of our speculation about the phenomenal experience of other species had, until this fraught and chaotic moment, been constrained to our affinities with other living creatures, for excellent reasons.
We have since persuaded ourselves that the difference between the essential realities of animate and inanimate has been obliterated. In that conceptual wreckage it becomes possible to attribute to inanimate objects some important things proper to our human nature.
This is a new idolatry, congenial to modern sensibilities, yet one that seems so familiar.
The Psalmist complains that
…their idols are silver and gold, the work of human hands. (115:5 ESV)
They have mouths but do not speak, and eyes but do not see.
They have ears but do not hear; noses but do not smell.
They have hands but do not feel; feet but do not walk… (115:5-7)
And the result is
Those who make them become like them;
so do all who trust in them. (115:8)
Man, made in the image and likeness of God, is in the process of constructing a god made in the image of man, and having made this god, surrendering to it, and worshipping it.