Eat your heart out Thomas Nagel

My recent piece on John Locke and consciousness generated some interesting discussion, which I'll try and collate here soon. In the meantime, a piece on Ian Wardell's blog got me thinking along quite different lines : what if disembodied consciousness were possible ? What would it be like to be a ghost ?

A ghost is popularly depicted as a floating white sheet with eye holes transparent person. Typically they have essentially the same attributes as real people, usually with rich memories, perfectly ordinary senses like sight and touch, and are often subject to strong emotions. They differ in that they interact with the physical world rather differently to ordinary mortals, but basically they're just see-through people.

I think a true disembodied consciousness, if it were even possible, might be something else entirely.

If consciousness is allowed to exist outside the body, then this mandates some form of dualism. For this to be possible the world itself cannot be made of consciousness (idealism) but some distinct, physical stuff, some substrate in which our ghost shall exist. So we shall allow it to exist in the world but not be of the world. You cannot have ghosts in the idealist or materialist case, at least not in any meaningful sense. We must accept dualism for this exercise or there's no point to it.

Now Plato, at times, advocated for following the path of pure reason, arguing that the senses deceive us. If we want truth, he suggested, we have to abandon the senses and give ourselves over to pure thought. But if we did that, what would we perceive ?

We know that the structure of our eye and the corresponding nervous system play as much a role in what we see as much as what's actually there to observe in the first place. Qualia are not completely independent of reality or totally subjective either. As Locke said, you can't just imagine entirely new qualia. You can recall those you're already familiar with and modify them, but not create them. 

So would a ghost perceive anything at all ? Would it perceive realty directly, without any of the errors of the senses, or nothing whatsoever ?

I lean towards the latter. If reality is external, objective, and real, as it must be in our dualist scenario, then our perceptions are limited and flawed, but rarely can they be said to be wholly "wrong". So to truly know the world fully requires more perception, not less. But our disembodied consciousness must, by definition, have no senses or it is not disembodied - it would have a distinct physical connection to the world. If instead we want to imagine a being with perfect and complete perception, we are imagining God, not a ghost. And that's a different exercise altogether. No, our ghost shall have no perception, but it must of course have experience.

Our ghost is blind, then. It is a creature of pure subjective awareness.

Perception and the capacity for experiential awareness requires memory. In order to read the world you must have some understanding and knowledge of it, which is impossible without memory; the same applies to internal experience just the same. More fundamentally, existence demands continuity, which for our being of pure consciousness necessitates memory. A ghost, it would seem, must therefore have memory or it has nothing.

But this is awkward, since we know that memories are stored within the brain and body. Where then would our ghost store its memories ?

The subjective experience of the world is qualia. Does memory itself constitute a qualia, or does whatever prompts our memory only re-induce those same qualia in us ? I incline to the latter. As a book contains words which are themselves physical, objective, and real, but induce within us purely subjective experiences, so do the brain (and body) store memories. Qualia are not stored themselves (being non-physical in nature they perhaps cannot be), the brain only reminds us of what it experienced before. To recall a memory is, in a sense, to repeat an experience, albeit to a lesser and more imprecise degree than in the original conditions.

So would a ghost be able to comprehend and consider qualia ? What would induce them if it had no physical apparatus with which to sense ? What, if anything, could it remember for further assessment ? If it lacked memory entirely - if it existed only in the moment, with no ability to assign meaning to anything - then I do not see how it could be called conscious. Again, memory (though not memory of being a mortal human) would seem to be a necessity, otherwise a disembodied consciousness could not meaningfully be said to even exist. We must therefore accept for the sake of argument that the ghost has memory, after a fashion - presumably as pure qualia, with none of the neuronal heuristics of the physical brain. 

Which, without senses, must be how the ghost exists more generally also : a creature entirely of pure sensation, pure subjectivity, unbound by physical reality. If it did have senses, it would be able to interact with the world, and for all intents and purposes I do not see how we could really call it a "ghost" at all - it would instead be like someone "out of phase" in a science fiction show.

(And yet, perhaps not wholly without senses after all, though undeniably different from the senses we're used to considering.)

Without senses, but possessing memory, our ghost would akin to the proverbial brain in a vat. At best, if such a being of air and darkness could somehow be perceived, small wonder its actions would seem as if on a replay. It would have no new information on which to make choices, only rearrangements of what it already knew. At worst it would be incoherent, as though in a dream. In this mental state there are no constraints whatsoever, nothing to give the world structure and consistency but our own fancies. If the brain and the body are what provide limits and structure to our thoughts, our lone ghost would have nothing to provide it with the stability of a mental framework.

Unless, perhaps, there were other ghosts - reference points and sources of new information, new perspectives on which to act. Then this world of shadows and dust would not quite be one of pure imagination. While still radically different from ordinary reality, and far removed from the crude imagery of ghosts-as-transparent-people meme, it would yet be more similar to everyday life : each ghost responding to the others in new and unpredictable ways, a genuine afterlife of sorts, not an incoherent and nonsensical mass of useless sensation.

(An alternative view is that it is consciousness itself which provides structure to matter, that matter is shaped entirely by mind rather than the other way around. But if that's the case, if mind is all-powerful, then I do not see why it would be so determined to construct itself such crude and pointless hosts*. No, it is mind from matter which is most appealing to me. Yet there seems an undeniable interplay between the two, rather than demanding a total superiority of one or the other.)
* In other words, why aren't I Jason Momoa ?

We must consider also that pain and pleasure are also qualia. This leads to the uncomfortable prospect of our ghost's world as one of eternal bliss or eternal torment, or a mingling of both.

Or does it ? For a singular consciousness perhaps not, for there would be nothing to induce it. Then again, the mere memory of pain (as Locke noted) hardly compares with the real thing. But psychological distress, anxiety... are those internal ? Worry and doubt are not the same as the pain of dismemberment, but can be debilitating all the same. Fear is perhaps the literal mind-killer.

The Death of the Discworld experiences emotions, but differently to humans. Lacking hormones, he can think angry, but not feel angry. Even feelings and emotions are, arguably, different from one another, still more so from thoughts. Likewise in Greek mythology, the spirits were mere shades of their former selves, not at all as vibrant or vital (as it were) as real people. So our afterlife might be dim indeed, a realm of pale shadows - lacking the errors of our senses, yes, but hostage to the errors of our subjective judgements.

Think of smell. I find it much more difficult to imagine a smell than an image - I can do it, but to a very limited extent. I can imagine a loaf of bread in some considerable visual and even tactile detail - the texture, the colour, the feel of it, the flecks of flour and seeds - but the smell is harder. Put an actual fresh loaf in front of me and the sensation comes freely with all its richness, but without that direct perception, the qualia of smell is weak indeed. So too might be the realm of the ghosts, little more than an echo. The constraints provided by other consciousnesses would not seem as strong as the far stricter limitations imposed by the brain and body, which keep our thoughts ordered and whole. The afterlife might be vague and faint - far more prone to confusion and obscurity, not less as Plato thought.

Then again, dreams do not always seem so formless. Indeed, their sensation often seems vivid and intense until we awake, and only then does the memory diminish. Is this because, when dreaming, we exist in some realm of pure qualia, and thus our "perception" is wholly dominated by them ? Or is it that the sensations are generated and amplified by the same apparatus we use for real perception, without which we would have little or no clarity or awareness whatsoever ?

To be a ghost would not necessarily mean we would be anything like a traditional spectre. Stripped of all our physicality, we would be left with (assuming it to be possible at all) pure awareness, emotion, and memory. And even the quality of those might not in any way resemble what we're used to : lacking all our usual senses, hormones, and other bodily conditions that demonstrably influence us, it's hard to see how life as a ghost could much resemble life as a mortal.

Even more radically : what of time ? According to relativity, photons (i.e. energy) do not experience time. If our ghost is energy, then, its existence becomes utterly unfathomable. Perhaps it would escape the problems of memory (there would be no time in which to store them, nor any sense of continuity or change), but its whole nature would become so radically different to our own that speculation on its subjective experience would become truly meaningless.

I do not believe ghosts exist. And while I'm even more certain that my speculations here are far from complete or even correct, I for one won't be trying a Ouija board any time soon. The ghost, so far as I can tell, would have nothing much to say.