by Quinn O'Neill
My position is not so much that we can exist in more than one body but that we don’t know that we can’t, or even how probable it would be. To be clear, I'm not suggesting any kind of dualism or that we might be reincarnated with our current attributes and personality traits. Consistent with a naturalistic view of the world, I accept that consciousness and perception of self are generated by the brain, so when the brain dies there's nothing left – no thoughts, no personality, and no spirit. The chance of an identical physical copy of my brain arising again is very small, so perhaps I needn't worry.
But it’s here that the worry creeps in. Is an identical physical copy of my brain what it would take for me to experience being alive again? In order to establish that subjective consciousness is restricted to a single body, we'd have to understand how it works and we really don't.
From a naturalistic perspective, the brain is what makes us who we are. Presumably, if we could create perfect physical copies of ourselves right down to the wiring of our brains and the neural connections that store our memories, we could effectively recreate ourselves. But there’s a problem, because even if I could perfectly replicate myself and make a thousand copies, I would perceive only one of these as “self”. In other words, whatever makes me uniquely me is not something that I could even in theory share with an identical physical copy. The only thing that could distinguish me from such copies is position. Only the location of my perspective would be unique.
This is a bit of a conundrum. To an objective observer encountering me and one of my copies, there’d be two identical copies of me, each thinking itself the original. From my point of view, however, there’d be a big difference between the copies – I’d be one of them and the other would be someone else.
The question to answer in deciding whether I could exist in another body may be what makes a perspective mine. This would seem to be largely independent of physical composition if an identical physical copy could have an entirely different perspective. What then would determine which copy I would perceive as self? Would there be an equal probability of my perspective being located in any copy or might I exist in some kind of superposition, like Schrödinger’s cat?
We can resolve this issue by acknowledging that the copies couldn’t be perfectly identical, since they would invariably be dissimilar below a molecular level. However, if the uniqueness of a subjective consciousness is attributable to such minute differences in composition, a unique subjective consciousness would be transient since matter is in a state of flux. Not only would it be unlikely that I’d ever exist in another body, it’d be unlikely that I’d exist in my current body in, say, five minutes – that person will be someone else, defined by a slightly different composition. We don’t have any empirical way to confirm that our present subjective consciousness spans a bodily lifetime. We only know that we are conscious now.
Steve Grand puts things in perspective nicely in his book, Creation: Life and How to Make It. He says: “[Think] of an experience from your childhood. Something you remember clearly, something you can see, feel, maybe even smell, as if you were really there. After all, you really were there at the time, weren't you? How else would you remember it? But here is the bombshell: you weren't there. Not a single atom that is in your body today was there when that event took place . . . Matter flows from place to place and momentarily comes together to be you. Whatever you are, therefore, you are not the stuff of which you are made. “
From a naturalistic point of view, however, you are the stuff of which you are made and you weren’t present for your childhood. Memory creates the perception of continuity, but it may be an illusion; a unique consciousness generated by a very precise material composition couldn’t be persistent.
Many people will readily assert that we each get one life and that when you die, that’s it. But we don’t really have any reliable way to gauge the likelihood that a particular subjective consciousness is persistent or that it’s a one-time-only event. Investigating subjective experience scientifically is difficult since subjective phenomena generally don’t lend themselves to empirical investigation.
This difficulty is well recognized by scientists. John Maynard Smith, who was a widely respected evolutionary biologist, in an interview with Robert Wright, offered this comment: “I’m quite clear in my mind that I do not understand consciousness, that I have nothing sensible or intelligent to say about it, that I don’t even have any good ideas for experiments or investigations that would shed light on it. What I don’t know is whether it’s possible to have intelligent ideas about how we might investigate it.”
As individuals we can’t know for sure that other organisms, even other people, experience subjective consciousness as we do. Much of human behaviour could be explained without it. The withdrawal of a limb from a painful stimulus, for example, could be purely reflexive without any subjective experience of pain. Richard Dawkins nicely expressed the difficulty in knowing whether other people and animals are conscious in a 2009 interview for Big Think. Asked if there is a certain brain capacity necessary for the development of consciousness, he responded “nobody knows, because we don't know which animals are conscious. We don't actually, technically, even know that any other human being is conscious. We just each of us know that we ourselves are conscious. We infer on pretty good grounds that other people are conscious, and it's the same sort of grounds that lead us to infer that probably chimpanzees are conscious and probably dogs are conscious. But when we come to something like earthworms and snails, it's anybody's guess.”
Evolutionary biologists aren’t necessarily the best positioned to elucidate the basis of subjective consciousness and scientists in other fields have contributed to this effort. It’s worth noting that there are a number of hypotheses that incorporate quantum mechanical phenomena. These might be particularly relevant to the hypothetical scenario with identical physical copies, since such copies would differ mainly at atomic and subatomic levels at which quantum rules come into greater play.
While quantum hypotheses may reflect progress in our understanding they remain controversial. For the moment, at least, subjective consciousness doesn’t seem to be well enough understood to rule out the possibility of recurrence. Not knowing exactly what material entities or neurophysiological processes give rise to a unique subjective consciousness, we can’t affirm that it won’t arise again at some point in the future.
I find this possibility of recurrence frightening. Being somewhat cognizant of recent events around the world and the conditions in which some people live, I realize how lucky I am to have been born in a stable, developed country to parents who could feed me and send me to school. If my subjective consciousness were to arise again someday, I probably wouldn’t be so lucky.
While I don’t believe in a supernatural Hell, human suffering can certainly reach hellish proportions on Earth. If the threat of going to Hell after death is enough to inspire moral behavior, the possibility that one’s subjective consciousness might someday recur should be a powerful impetus for improving circumstances for people on earth. We might even want to rethink our treatment of animals – at least until we can be sure that we won’t someday see the world through the eyes of a circus elephant or a beef cow.
Photo credit: nickandmel2006 at flickr; licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.