you are joking, aren't you?
Are you really suggesting that there is not a cumulative improvement in medical science?
Is packing the womb in ice as good a treatment for hysteria as a sedative?
Is bloodletting with leeches as good a treatment for high blood pressure as the current rest and low fat diets?
You don't think that the discovery of the circulatory system was an advance over the view that the blood was forced out into the body and them flowed back again?
Or that the identification of air-borne bacteria as the source of infection was an advance?
Or the development of anaesthetics? Or vaccinations? Or the matching of transplant tissue? Or the identification of viruses?
Medical science does present one interesting paradox in that by far the greatest number of advances are concentrated in the last two hundred years, but there is not a shadow of a doubt that the cumulative store of medical science has developed immeasurably (except I suppose in the minds of faith healers and other nuts).
It is pointed that the one example you identify, that of public health advice, is the area that is most governed by political rather than simply medical considerations. It is true that there have been some erratic fluctuations in health advice, mostly because of the excessive desire on the part of government authorities to be seen to be doing something.
But even there I think you will find a pretty stark unanimity on the health risks of smoking (since the fifties in Britain and America, in the 1930s in Germany), or the superiority of low fat diets, or the advisability of regular exercise.
-- Jim heartfield