No, we can't. A vivid image of what should exist acts as a surrogate for reality. Pursuit of the image then prevents pursuit of the reality -- John K. Galbraith
But of course, measuring the value of a treatment in survival rates is a very Modern(TM) way of looking at the world, that may not be Helpful to the patient.
- Jake If you only spend 20 minutes of the rest of your life on economics, go spend them here.
New Scientist (where else?) had an interesting feature earlier in the year about the relative effectiveness of drugs, and how there's solid evidence that objectively influenced by the placebo effect and by the confidence of the patient in what is - often - as much a ritualistic activity as a scientific one. Doctors reliably hand out ineffective tablets and get positive results. How is that not voodoo?
So far as I know, shamanistic cures have only very rarely been studied objectively, so there's very little evidence for their effectiveness, or lack of it.
What passes for shamanism in the West is usually based on silly white people buying themselves a drum after a package holiday to Siberia or a weekend in a slightly remote part of Wales. I'd be surprised if it has much in common with the real thing, which - by all acounts - can kill you if you don't learn it properly, and will probably drive you mad even if you do.
The fact that frontline Western doctors (and vets) are very suicide prone is possibly just a coincidence.
It's a continuum - not all of the action happens at either extreme.