Information about the brain is not the same as information in the brain; yet in discussions of mind uploading, brain simulation, and mind reading the two are quite often conflated or confused. Equivocating between the two makes the task seem far easier than it really is. Scanners of various kinds exist, after all, and have greatly improved in recent years; technology usually goes on improving over time. If all we need is to get a really good scan of the brain in order to understand it, then surely it can only be a matter of time? Alas, information about the brain is an inadequate proxy for the information in the brain that we really need.
We’re often asked to imagine a scanner that can read off the structural details of a brain down to any required level of detail. Usually we’re to assume this can be done non-destructively, or even without disturbing the content and operation of the brain at all. These are of course unlikely feats, not just beyond existing technology but rather hard to imagine even on the most optimistic view of future developments. Sometimes the ready confidence that this miracle will one day be within our grasp is so poorly justified I find it tempting to think that the belief in the possibility of such magic scans is being buoyed up not by sanguine technological speculation but unconsciously by much older patterns of thinking; that the mind is located in breath, or airy spirits, or some other immaterial substance that can be sucked out of a body and replaced without physical consequences. Of course on the other side it’s perfectly true that lots of things once considered impossible are now routinely achieved.
But even allowing ourselves the most miraculous knowledge of the brain’s structure, so what? We could have an exquisite plan of the structure of a disk or a book without knowing what story it contained. Indeed, it would only take a small degree of inaccuracy or neglect in copying to leave us with a duplicate that strongly resembled the original but actually reproduced none of the information bearing elements; a disk with nothing on it, a book with random ink patterns.
Yeah but, the optimists say; the challenge may be huge, the level of detail required orders of magnitude beyond anything previously attempted, but if we copy something with enough fidelity the information just is going to come along with the copy necessarily. A perfect copy just has to include a perfect copy of the information. Granted, in the case of a book it’s not much use if we have the information but don’t know how to read it. The great thing about simulating a brain, though, is that we don’t even need to understand. We can just set it up and start it going. We may never know directly what the information in the brain was, but it’ll do its job; the mind will upload, the simulation will run.
In the case of mind reading the marvellous flexibility of the mind also offers us a chance to cheat by taking some measurable, controllable brain function and simply using it as a signalling device. It works, up to a point, but it isn’t clear why brain communication by such lashed-up indirect routes is any more telepathy than simply talking to someone; in both cases the actual information in the brain remains inaccessible except through a deliberate signalling procedure.
Now of course a book or a disk is in some important ways actually a far simpler challenge than a brain. The people who designed, made, and use the disk or the book take great care to ensure that a specific, readily readable set of properties encodes the information required in a regular, readable form. These are artefacts designed to carry information, as is a computer. The brain is not artefactual and does not need to be legible. There’s no need for a clear demarcation between information-bearing elements and the rest, and there’s no need for a standardised encoding or intelligible structures. There are, in fact many complex elements that might have a role in holding information.
Suppose we recalibrated our strategy and set out to scan just the information in the brain; what would we target? The first candidate these days is the connectome; the overall pattern of neural connections within the brain. There’s no doubt this kind of research is currently very lively and interesting – see for example this recent study. Current research remains pretty broad brush stuff and it’s not really clear how much detail will ever be manageable; but what if we could map the connections perfectly? How could we read off the content? It’s actually highly unlikely that all the information in the brain is encoded as properties of a network. The functional state of a neuron depends on many things, in particular the receptors and transmitters; the large known repertoire of these has greatly increased in recent years. We know that the brain does not operate simply through electrical transmission, with chemical controls from the endocrine system and elsewhere playing a large and subtle part. It’s not at all unlikely that astrocytes, the non-neural cells in the brain, have a significant role in modulating and even controlling its activity. It’s not at all unlikely, on the other hand, that ephaptic coupling or other small electrical induction effects have a significant role, too. And while myself I wouldn’t place any bets on exotic quantum physics being relevant, as some certainly believe, I think it would be very rash to assume that biology has no further tricks up its sleeve in the shape of important mechanisms we haven’t even noticed yet.
None of that can currently be ruled out of court as irrelevant. A computer has a specified way of working and if electrical interference starts changing the value of some bits in working memory you know it’s a bug, not a feature. In the brain, it could be either; the only way to judge is whether we like the results or not. There’s no reason why astrocyte states, say, can’t be key for one brain region or for one personality, and irrelevant for others, or even legitimate at one time and unhelpful interference at others. We just cannot know what to point our magic scanner at, and it may well be that the whole idea of information recorded in but distinct from a substrate just isn’t appropriate.
Yeah but again, total perfect copy? In principle if we get everything, we get everything, don’t we? The problem is that we can’t have everything. Copying, simulating, or transmitting necessarily involve transitions during which some features are unavoidably left out. Faith in the possibility of a good copy rests on the belief that we can identify a sufficient set of relevant features; so long as those are preserved, we’re good. We’re optimistic that one day we can do a job on the physical properties which is good enough. But that’s just information about the brain.