I know what you're getting at; you obviously can't measure pain in the same way you can measure blood pressure or heartrate (both of which, by the way, are affe

I know what you're getting at; you obviously can't measure pain in the same way you can measure blood pressure or heartrate (both of which, by the way, are affected by placebo.) But it's abject nonsense to extend that to the idea that you can't measure pain at all. Do you claim that the effect of opioids on pain is unmeasurable?