This blog is closely related to my previous blog – “Stuart Derbyshire on foetal pain”. In that blog I reported that Stuart now rejects his former view that foetuses and early stage infants can’t feel pain because of a change in his theoretical position not because new evidence had emerged. This was intended to highlight the importance of theories and concepts. My target here is clarity; ambiguous concepts can have significant consequences.
Although I didn’t mention it in my previous blog, Stuart takes it that the International Association for the Study of Pain’s (the IASP’s) definition of pain requires higher-order mental capacities. In short, the idea that the development of the self is required for pain experience (see my previous blog for a bit more explanation of the ‘higher-order theory of pain‘). The IASP is so highly regarded that their understanding of what is required for pain really matters. (Here’s the link to the IASP’s taxonomy of pain terms.)
I’m pretty sure that Stuart’s misinterpreting the IASP’s definition (I’ll explain why in a moment), but for now let’s pretend that he’s right. This would mean that the IASP is sanctioning the theory that higher-order mental capacity is required for pain. Therefore, any living thing lacking this capacity wouldn’t be able to experience pain. So, according to pain science, foetuses, the new-born and many non-human species of animal wouldn’t feel pain. From this you can see that the mainstream adoption of a particular theory can have very important practical and moral consequences; foetuses, early stage infants, and non-human animals might be denied anaesthesia and analgaesia.
The worry that the IASP’s definition amounts to the official sanction of a higher-order theory of pain fuels a debate that still simmers today. (This debate was sparked by Anand and Craig’s 1996 paper, “New perspectives on the definition of pain” – unfortunately this paper is not open access.) But these concerns can be put down to a misreading of the IASP’s ambiguously worded definition: pain is “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”
What is meant by “associated with actual or potential tissue damage…” and “described in terms of…” is far from clear. Although there’s an explanatory note that accompanies the definition in the IASP’s taxonomy, it’s not very helpful. Over the years I’ve thought quite a lot about the definition and note. The ‘association’ and ‘description’ might be interpreted as requiring higher-order mental capacities (to associate and to describe), but I’ve come to think that the definition means this: pain is
- Either an unpleasant sensory and emotional experience caused by actual or potential tissue damage,
- Or an unpleasant sensory and emotional experience that feels just like an unpleasant sensory and emotional experience caused by actual or potential tissue damage.
I’m not saying that 1 and 2 are either clear or satisfactory as a definition. What I’m saying is that from the definition and note (and plenty of reading between the lines) it looks as though the IASP (and by extension mainstream pain science) intend something like 1 and 2. And 1 and 2 do not require higher-order mental capacity for pain. So the IASP’s definition does not exclude the possibility that animals lacking this capacity can feel pain.
My understanding is supported by a reformulated definition that was recently proposed (but not yet, as far as I’m aware, ratified) by the IASP’s taxonomy committee: pain is “An aversive sensory and emotional experience typically caused by, or resembling that caused by, actual or potential tissue injury“.
In my view, this reformulation would be unsatisfactory for several reasons (lack of clarity being one reason), but I’ll wait to see if it’s ratified before further comment. The point of this and my previous blog has been to illustrate the importance of concepts and theories. Broadly speaking, good science requires clear and coherent concepts and theories to frame experimental design and data. The evidence I’ll present over time shows that pain science has favoured the latter at the cost of the former.
The Pain Jam 