Your anaesthetist comes and talks to you before your surgery. Following his thorough yet efficient pre-operative assessment he tells you that it may be possible that his anaesthetic is simply a perfect amnesic agent. You could potentially experience the entire operation in the moment (unable to move or do anything about it) but at the end you would have absolutely no recollection of these events. You would ‘wake up’ from the anaesthetic with a perfect gap in your episodic memory; to all intents and purposes a period of ‘unconsciousness’. No one would know if you experienced anything (particularly you), and it would be exactly as if you hadn’t. But maybe you had.
Would this bother you? And if it did, why?
Let’s dive into some of the conflicting intuitions that I have on this topic. My first instinct is that of course it matters. As a conscious agent I would be aware of someone sticking a knife into me, manipulating internal parts of my body and then sewing me up, all the while being unable to move. The process of imaging what this would be like is quite unpleasant, and gives me additional empathy towards anyone that has experienced awareness under anaesthesia. It is not something that I would wish on myself or anyone else, and would fill me with a dread of having to have an operation if I knew that this was what happened.
However, I must then ask myself “maybe this has happened to me!?” I have had an operation, for which I had an anaesthetic. I have complete amnesia for the period of my general anaesthetic (and some of the recovery period) and that is all I can actually say about that event. From my perspective now, the contrasting alternative experiences of myself at that time (unconscious versus aware-but-amnesic) are genuinely indistinguishable from each other. If I had had the complete amnesia experience, then I now genuinely don’t care about it. Primarily because, from my current perspective, it didn’t actually happen to me. It seems that in order for it to have happened to me (the current me who is writing this blog post), it does seem to need to be psychologically connected to my current self. I can raise a similar question for when we sleep. I don’t remember my non-REM sleep and yet my brain is very active at this time. Am I ‘conscious’ of any of this neuronal activity and simply amnesic of it, or am I genuinely unconscious throughout (perhaps this example says more about the mysteries of sleep and consciousness than anything else though). Either way, I don’t have any psychological connection to this sleeping version of me and it doesn’t seem to bother me if I happened to routinely spend these hours in torment as my brain reorganises itself and then deletes my memory of the period.
To bring this abstract thought experiment closer to reality, I feel that I have seen cases like this. Some cases of conscious sedation appear to be having consciousness at the time of certain procedures (evidenced by appropriate motor activity) but profess absolutely no recall afterwards. I have even seen an example where they were still awaiting the procedure that had already happened. Admittedly the complete unawareness of the procedure was not part of what was offered from the sedationist here (something that I am very clear about in the consent process for any cases of conscious sedation that I do) but they seem to have still managed to end up with the same final outcome as our general anaesthetic case. I concede that I have not done a detailed follow up to analyse how dense their amnesia truly was, but the point remains. And much more commonly than these cases are when we routinely see the preservation of the nociceptive response to noxious stimuli in patients who are under general anaesthesia. It is only retrospectively that we can truly label these as nociception rather than pain, when we establish that there was no conscious component to it. However, there is clearly a neurologically mediated physiological response going on here which, if we are physicalists about the nature if consciousness, is all that consciousness really is. We are simply much more reassured that consciousness isn't present by the visible correlates of this: the absence of appropriate motor activity, the presence of associated EEG patterns (if monitoring these), and (the topic of this post) the lack of any recall after the event. Indeed, some motor reflexes appear to persist despite 'deep' levels of anaesthesia - something that gave me quite a shock when I first started anaesthesia training. Even now I get a bit of a jump when I see an unexpected spike on my BIS monitor. This leaves the absence of recall of the events as the ‘gold standard’ of our anaesthetic, with a problematic retrospective nature to it.
All of this brings me to a sense that, although we are pretty convinced that people are not conscious, much of this is founded on these visible correlates. The biggest reassurance is the very reliable lack of recall, but this is identical in the 2 alternative situations initially described. This therefore brings me back to the relevance of the second question: "should we care?" When I think about this question I get a very strange sense of time-dependency to it. It is ‘me’ when the event is in the future (I am concerned about what ‘I’ will have to experience), but it is not ‘me’ when the event has passed (I don’t even know that anything happened). My answer is therefore somewhat dependent on when you ask me although I would still tend towards saying that it does matter. Even if the ‘past me’ feels very separate from the ‘current me’, I can still imagine that his experience is an unpleasant one to go through and I have some empathy with this ‘stranger’. This would seem to negate the argument of amnesia, given that someone has had to go through that experience, even if that person doesn't really ‘exist’ any more after the event, as the amnesia kicks in. In my mind it is probably this factor that we need to weigh most strongly when we are answering this second question. Someone is suffering and this seems ethically undesirable.
So let’s wrap up. I think there are some fascinating questions thrown up by this thought experiment, flagging up some of the real complexities of consciousness, personal identity, memory, and the mysteries of anaesthesia. I am personally quite swayed by the importance of psychological continuity as a core part of our personal identity. This has left me a bit puzzled over the significance of the different cases here. However, it seems clear that the presence of any consciousness during such an unpleasant event as surgery is highly undesirable, regardless of its duration or impermanence. Indeed, this is part of the brilliance of anaesthesia. It is a central part of our role as anaesthetists to be able to bring this true unconsciousness, and it is clear that amnesia is not good enough, no matter how confident we could be with it. It seems a rare scenario where we would be forced into this problem, but should still remain a guiding principle to our clinical approach.
Links & References
- Locke, J. Of identity and diversity, in: An essay concerning human understanding. 1689. Available at: http://www.gutenberg.org/cache/epub/10615/pg10615.html
- NAP5: Accidental awareness during general anaesthesia in the UK and Ireland. https://www.nationalauditprojects.org.uk/NAP5home