I think I'd say a comination of clinical professionalism (the art of it) and science, jane.
Love the joke, nightowl 
Further, jane, I don't think Goldacre would knock the scientific method. Yes, science is sometimes (often?) flawed, but if scientists stick with the scientific method, in time those flaws will be corrected. That is the beauty of science. When it is discovered that some 'belief' is wrong, you discard it in favour of a better one. I think jess would back me up on that and maybe say it a bit better too.
So, yes, I'm all for science being challenged. And if doctors think the cirrent state of knowledge is inadequate for their needs, which I'm sure it often is (we don't know everything by a long chalk), of course they must use their professional judgement based on experience and so forth.