A few days ago, when I was out walking, I ran into someone I’d met very briefly on holiday in Greece at the end of last year. It was one of those, ‘don’t I know you from somewhere’ meetings. The other day, without prompting, Pete began to talk about pain AND he perfectly quoted the International Association for the Study of Pain’s (the IASP’s) definition of pain. To say that I was surprised would be an understatement. It turns out that Pete’s professionally involved in pain; he’s an anaesthetist and he teaches pain to medical students. Feeling puckish, I couldn’t resist asking what the IASP’s definition means. To which he replied, “It’s not very clear is it; and it doesn’t apply to pathological pain [pain caused by damaged nerves or adaptive changes to the nervous system that have a harmful effect].” This statement, from someone who’s professionally involved in teaching pain, is a powerful illustration of the opacity of the IASP’s definition because it’s incorrect. But that’s not my point. It was his follow-up that struck me; “Of course, the IASP’s definition doesn’t matter because we all know what pain is.” My intuition is that most people would agree with Pete. It certainly explains the survival of the IASP’s wholly inadequate definition; most experts don’t care about the IASP’s definition because they think almost everyone knows what pain is. It’s the sensation you get when you bash an elbow, when you prick yourself on a thorn, get cramp or when you touch something hot.
What Pete means is that most of us are able to correctly identify whether an experiences is a pain or whether it’s not a pain. How do we do this? In short, we learn what pains feel like through, as the IASP put it, “experiences related to injury in early life” (2017 – see the IASP’s taxonomy of pain terms here). The way these experiences feel (their subjective character) gives us a template for pain. If an experience fits the template then the subject of that experience will judge that it’s a pain, and vice versa. The million dollar question is whether these judgements are reliable. This is a complex matter.
If pain were to be defined in accordance with Pete’s claim that we all know what pain is, then first-person judgements must be reliable. In fact, they’d be infallible: an experience is a pain because it has been judged (or would be judged) a pain by its subject who compares the fit of that experience with her pain template; or an experience is not a pain because it’s been judged (or would be judged) a non-pain by its subject who compares the fit of that experience with her pain template. While a different type of definition, which is not based on first-person judgement, does not imply unreliable first-person judgements it leaves open the question of whether first-person identification of an experience as pain (or a non-pain) is reliable.
My view is that scientific endorsement of the sort of subjective definition suggested by Pete’s ‘we all know what pain is’ would represent an endictment on the status of pain science. It’s true that pain science began as an investigation of the experiences we identify as pain using our pain template, but after many years of research and conceptual development we should expect the scientific definition of pain to deviate from this ordinary notion. I’m not going to go into my reasoning here, but I think that the IASP’s definition (“An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage” – IASP, 2017 – see the IASP’s taxonomy of pain terms here – ) is an endorsement of the ordinary notion. This strongly suggests that pain science is still in its infancy. There’s certainly a great deal of work to be done!
The Pain Jam 