A digital afterlife is likely to be available one day, according to Michael Graziano, albeit not for some time; his piece re-examines the possibility of uploading consciousness, and your own personality, into a computer. I think he does a good job of briefly sketching the formidable difficulties involved in scanning your brain, and scanning so precisely that your individual selfhood could be captured. In fact, he does it so well that I don’t really understand where his ultimate optimism comes from.
To my way of thinking, ‘scan and build’ isn’t even the most promising way of duplicating your brain. One more plausible way would be some kind of future bio-engineering where your brain just grows and divides, rather in the way that single cells do. A neater way would be some sort of hyper-path through space that split you along the fourth spatial dimension and returned both slices to our normal plane. Neither of these options is exactly a feasible working project, but to me they seem closer to being practical than a total scan. Of course neither of them offers the prospect of an afterlife the way scanning does, so they’re not really relevant for Graziano here. He seems to think we don’t need to go down to an atom by atom scan, but I’m not sure why not. Granted, the loss of one atom in the middle of my brain would not destroy my identity, but not scanning to an atomic level generally seems a scarily approximate and slapdash approach to me given the relevance of certain key molecules in the neural process – something Graziano fully recognises.
If we’re talking about actual personal identity I don’t think it really matters though, because the objection I consider strongest applies even to perfect copies. In thought experiments we can do anything, so let’s just specify that by pure chance there’s another brain nearby that is in every minute detail the same as mine. It still isn’t me, for the banal commonsensical reason that copies are not the original. Leibniz’s Law tells us that if B has exactly the same properties as A, then it is A: but among the properties of a brain are its physical location, so a brain over there is not the same as one in my skull (so in fact I cheated by saying the second brain was the same in every detail but nevertheless ‘nearby’).
Now most philosophers would say that Leibniz is far too strong a criterion of identity when it comes to persons. There have been hundreds of years of discussion of personal identity, and people generally espouse much looser criteria for a person than they would for a stone – from identity of memories to various kinds of physical, functional, or psychological continuity. After all, people are constantly changing: I am not perfectly identical in physical terms to the person who was sitting here an hour ago, but I am still that person. Graziano evidently holds that personal identity must reside in functional or informational qualities of the kind that could well be transferred into a digital form, and he speaks disparagingly of ‘mystical’ theories that see problems with the transfer of consciousness. I don’t know about that; if anyone is hanging on to residual spiritual thinking, isn’t it the people who think we can be ‘taken out of’ our bodies and live forever? The least mystical stance is surely the one that says I am a physical object, and with some allowance for change and my complex properties, my identity works the same as that of any other physical object. I’m a one-off, particular thing and copies would just be copies.
What if we only want a twin, or a conscious being somewhat like me? That might still be an attractive option after all. OK, it’s not immortality but I think without being rampant egotists most of us probably feel the world could stand a few more people like ourselves around, and we might like to have a twin continuing our good work once we’re gone.
That less demanding goal changes things. If that’s all we’re going for, then yes, we don’t need to reproduce a real brain with atomic fidelity. We’re talking about a digital simulation, and as we know, simulations do not reproduce all the features of the thing being simulated – only those that are relevant for the current purpose. There is obviously some problem about saying what the relevant properties are when it comes to consciousness; but if passing the Turing Test is any kind of standard then delivering good outputs for conversational inputs is a fair guide and that looks like the kind of thing where informational and functional properties are very much to the fore.
The problem, I think, is again with particularity. Conscious experience is a one-off thing while data structures are abstract and generic. If I have a particular experience of a beautiful sunset, and then (thought experiments again) I have an entirely identical one a year later, they are not the same experience, even though the content is exactly the same. Data about a sunset, on the other hand, is the same data whenever I read or display it.
We said that a simulation needs to reproduce the relevant aspects of the the thing simulated; but in a brain simulation the processes are only represented symbolically, while one of the crucial aspects we need for real experience is particular reality.
Maybe though, we go one level further; instead of simulating the firing of neurons and the functional operation of the brain, we actually extract the program being run by those neurons and then transfer that. Here there are new difficulties; scanning the physical structure of the brain is one thing; working out its function and content is another thing altogether; we must not confuse information about the brain with the information in the brain. Also, of course, extracting the program assumes that the brain is running a program in the first place and not doing something altogether less scrutable and explicit.
Interestingly, Graziano goes on to touch on some practical issues; in particular he wonders how the resources to maintain all the servers are going to be found when we’re all living in computers. He suspects that as always, the rich might end up privileged.
This seems a strange failure of his technical optimism. Aren’t computers going to go on getting more powerful, and cheaper? Surely the machines of the twenty-second century will laugh at this kind of challenge (perhaps literally). If there is a capacity problem, moreover, we can all be made intermittent; if I get stopped for a thousand years and then resume, I won’t even notice. Chances are that my simulation will be able to run at blistering speed, far faster than real time, so I can probably experience a thousand years of life in a few computed minutes. If we get quantum computers, all of us will be able to have indefinitely long lives with no trouble at all, even if our simulated lives include having digital children or generating millions of digital alternates of ourselves, thereby adding to the population. Graziano, optimism kicking back in, suggests that we can grow in understanding and come to see our fleshly life as a mere larval stage before we enter on our true existence. Maybe, or perhaps we’ll find that human minds, after ten billion years (maybe less) exhaust their potential and ultimately settle into a final state; in which case we can just get the computers to calculate that and then we’ll all be finalised, like solved problems. Won’t that be great?
I think that speculations of this kind eventually expose the contrast between the abstraction of data and the reality of an actual life, and dramatise the fact, perhaps regrettable, perhaps not, that you can’t translate one into the other.