The definition is as follows: 

“An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. 

Note: The inability to communicate verbally does not negate the possibility that an individual is experiencing pain and is in need of appropriate pain-relieving treatment. Pain is always subjective. Each individual learns the application of the word through experiences related to injury in early life. Biologists recognize that those stimuli which cause pain are liable to damage tissue. Accordingly, pain is that experience we associate with actual or potential tissue damage. It is unquestionably a sensation in a part or parts of the body, but it is also always unpleasant and therefore also an emotional experience. Experiences which resemble pain but are not unpleasant, e.g., pricking, should not be called pain. Unpleasant abnormal experiences (dysesthesias) may also be pain but are not necessarily so because, subjectively, they may not have the usual sensory qualities of pain. 

Many people report pain in the absence of tissue damage or any likely pathophysiological cause; usually this happens for psychological reasons. There is usually no way to distinguish their experience from that due to tissue damage if we take the subjective report. If they regard their experience as pain and if they report it in the same ways as pain caused by tissue damage, it should be accepted as pain. This definition avoids tying pain to the stimulus. Activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause”.  

Questions: 

1. The first sentence in the defintion associates pain with tissue pathology. What follows in the Note refers to the ‘subjectivity’ of pain. There seems to be an epistemic priority in play between the ‘objective’ measure of pain in terms of tissue insult and the ‘subjective’ criterion of when to categorize an experience as pain. The definition appears to accord authority on the nature and amount of pain to the patient (first-person authority). If this is correct, then pain researchers are studying the objectively observable causes of a subjective experience, but not pain characterised as an objective physical state. According to the definition, all objective measures of pain (eg, neuroscientific explanations) are logically prior to the subjective ones. Is this analysis accurate? Not quite. The IASP definition is compatible with neuroscientific discovery of pain experiences as states of the brain; for then objective measures will likely have not less than equal epsitemic authority. Still, it is curious the definition grants this, but leaves open the question of the nature of pain. 

2. What might explain the epistemic priority in the IASP definition? I suggest that it is the first-person authority (near-infallability) of pain self-report. Consider the statements (1) and (1*): 

(1) I am in pain. 

(1*) Susan is in pain. 

What does ‘being true’ amount to in these statements? I think it amounts to something quite different. The truth of (1) is guaranteeed by truthfulness, since it is not liable to mistake or error, only to insincerity. I give three reasons for this claim: 

- (1*) can be verified, but not (1). Is there such a thing as my ‘finding out’ that I am in pain or ‘recognizing’ pain from my sensations?

- (1) cannot allow of error or doubt, but (1*) can. The subject of pain cannot misidentify himself/herself or misapply pain language (‘I thought I had a pain, but it was an itch, and it was Susan’s, not mine’ seems nonsensical);

- (1) does not express a knowledge claim, but (1*) does.