This piece in the Atlantic raises a question we have touched on before: anaesthesia. How do we know it works, how do we distinguish it from amnesia, and how much does it matter? What is supposed to happen is that when we get an anaesthetic injection, or gas, we simply stop feeling pain; possibly we stop feeling anything. It is certainly more complicated than that: the drugs used by doctors may simply stop us feeling pain – we more or less know with a local anaesthetic that that’s sort of what happens – but they may also, or alternatively, stop us remembering, or caring about, the pain; they may also merely stop us moving or complaining. Some of the drugs used by anaesthetists apparently do only one of the three latter things, with no direct influence on the pain experience itself.
This matters most obviously when things go wrong, and in the middle of a surgical operation a patient resumes consciousness while remaining paralysed, experiencing all the terrible pain of being cut open without being able to give any sign of it. Because of the memory-erasing effects of some of the drugs used we cannot be sure how often this happens, but it is accepted that sometimes it does.
This is one of those areas where the apparently airy-fairy disputes of philosophy suddenly get real. A number of people are sceptical in principle about the reality of the self, of consciousness, and of subjective experience: but I think you need to be quite bold to stick to scepticism when it involves dismissing pain on the operating table as a mere conceptual confusion, something we need not be too concerned about.
There is, however, little agreement about some fundamental issues. Does it matter if I feel terrible pain, but then forget about it completely? I’d say yes, but a friend of mine takes the opposite view: if he doesn’t remember it he considers that as good as not having had the experience in the first place. Of course I would have minded at the time, he says, but that’s not what we’re talking about; we’re talking about whether I should mind now. Ex hypothesi, if I’ve forgotten, my mind is in exactly the same state as if I never had the pain, and it’s incoherent to say I should worry about a non-existent difference.
I have to concede that my point of view opens up many more problems. Since memory is fallible, there might be lots of forgotten pains I should be worried about; but if I have a false memory of a pain that never happened, is that also a cause for concern? It’s possible to be in a state of mind in which one feels a pain but somehow does not mind it: but what if I start minding about it later? What if I forget that I didn’t mind? What if I did mind but the pain was actually illusory? What if I felt the pain unconsciously? And what if the memory then became conscious later? Or what if I felt it consciously but have only an unconscious memory? Do animals feel pain in the same way as we do? Do plants? If a drug dials my level of consciousness back to monkey level, dog level, chicken level, lizard level, ant level – does pain still matter? If I feel pain while operating on a protozoan mental level, does it matter more when I remember it on a fully human level? Do imaginative people suffer more (as, apparently, red-headed people tend to do)?
This may all sound stupidly speculative, but the questions are genuine and we’re talking about whether I’m in agony or not. It would be great if we could bring all this out of philosophy zone and into science, but there are problems there too. The Atlantic article recounts difficulties with the BIS monitor, supposed to provide a simple numerical reading for the level of consciousness based on electroencephalograph readings. Perhaps it’s not suprising that the BIS has been questioned: an electroencephalograph is hardly cutting edge brain technology. A more fundamental problem is that it has no known theoretical basis: the algorithm is secret and the procedure is based entirely on empirical evidence with no underlying theory of conscious experience. Providing sound empirical evidence of subjective experience is obviously fraught with complications.
Step forward our old friend Giulio Tononi, whose theory of Phi, the measure of integrated information and hence, perhaps, of consciousness, is ideally suited to fill the conceptual gap. With Phi in one hand and modern scanning technology in the other, surely we can crack this one? I don’t know whether the Phi theory is really up to the job: if it’s true it might tell me why consciousness occurs in the brain and how much of it is going on, but it doesn’t seem to explicate the actual nature of the pain experience, and that leaves us vulnerable because we’re still reliant on the fallible reports and memories of the patients to establish our correlations. Could we ever be in a position where the patient complains of terrible pain and the doctor with the Tononi monitor tells them that actually he can prove they’re not feeling any such thing?
Perhaps we can imagine a world where the doctor goes further. Great news, he says, we’ve established that you’re a philosophical zombie: although you talk and behave as if you have feelings, you’ve actually never felt real pain at all! So no injection for you – we’ll just strap you down and get on with it…