From comments at Greg Cochran’s blog:
* It’s a very engineering view of human nature to think that medicine is primarily about combatting disease, and whether what we’re doing actually works.
Part of what people want from medical care is precisely the care part, and this is because it makes them feel better. The care meets actual objective psychological demands, and the utility of this perhaps often exceeds the utility of a (quicker) cure. To some extent people behave as though they would prefer to be cared for, rather than cured.
In judging the efficacy of medical cures, patients buy into a socially-sanctioned belief structure, rather than doing any sophisticated cognitive assessment. Whether they feel cared for is something more directly within their own experience, and while trusting in the appropriate socially-sanctioned practices produces some of this sense of being cared for, it is not the whole of it: there’s also a tender manner, and human attention, and love.
Homeopathy works and survives because it is a medium for people to provide this care.
In instrumental terms, it invokes placebo responses, which is a valuable achievement in itself.
Perhaps most valuably, it reveals another dimension for understanding what we are really doing when we seek medical care and when we provide it to each other. What other social practices are primarily a medium of care?
We are then left to decide whether we can bring ourselves to tolerate people participating in a mistaken belief structure which does actually facilitate their access to this care, or whether instead we need to set them right and extirpate their heresy.