To understand the shift, we need to rehearse what is meant by ‘discursive practice’.
Despite what many secondary authors actually write, Foucault’s ‘archaeology’ is not primarily aimed at elucidating the contested meanings of what was said and done in the political heat of the times. What he meant by ‘discourse’ was not ‘a mere intersection of things and words… [but rather] practices that systematically form the objects of which they speak’ (Foucault, Archaeology of knowledge, 2002: 53-54).
Rather than watch the game as a critic, Foucault chose to ask on what grounds the crowd and the contestants and their critics could get together, adopt their roles, and unquestioningly know what was going on.
What has formed the ‘pain’ of which one today speaks such that it cannot be separated from the figure of the physician in the space of the clinic?
Before answering that, it may be best to illustrate that it need not be so. Just read the Book of Genesis or the Iliad and notice that what is inflicted on and suffered by the subject of pain is much at the whim of God, or the gods, and its meaning is moral, not clinico-pathological (as, after all, the latter form of perception was not to arise for centuries to come anyway). Sure, Hippocrates was interested in pain too, as a symptom that could help the physician to diagnose. But the morally meaningful nature of pain in the classic texts of our civilization is foremost, and it is not connected at all with the physician. God punishes Adam with the pain of hard toil, and Eve with the pain of labour as a punishment. (Keep in mind that pain and punish derive from the Latin poena, meaning penalty.) Similarly, the Greek and Trojan heroes die gruesomely, but surprisingly painlessly. It is only the nasty suitors (whom Odysseus slaughters once he gets home) who die ignominiously and painfully. Pain matters morally, not medically.
If you read Nietzshe’s Genealogy of Morals or Foucault’s Disipline and Punish you can also find discussion of the moral force that pain has wielded in societies. The infliction of pain is perhaps the most direct way of imprinting a memory of the moral code of the sovereign or of the priesthood. Pain gives terrible effect to power.
But today we imprison rather than torture (admitting exceptions!), and so pain retreats backstage in the drama of public morality, and the great industry of medicine takes up its cause, but in quite a different direction. For medicine, the affect of pain is presented beside a promise of painlessness; whereas morality and punishment used the realizable threat of pain as its affective principle.
The fact that today authors from any discipline outside of medicine, when writing of pain, seem to be tethered to the medical terminology and practice is suggestive of a transformation at the level of discursive practice. This is not to be dissociated, of course, from the wider complex of productive industries that address pain while using medical objectives and systems. I am referring in particular, of course, to the pharmaceutical industry that seeks (sometimes fraudulently) to extend the ‘promise of painlessness’ via analgesics and antidepressants.