Epidemiology, trials and medical knowledge

While there is an increasing attention on monitoring drugs for safety after being approved by the FDA -- including large registries to study drug use and its effects in the 'real world setting' -- it is still remarkable how much confidence we put in the present-day state of medical knowledge. An analysis piece in the New York times points to the interesting dynamic of establishing then refuting, or revising scientific knowledge that affects the medical treatment of millions of Americans. Here is an excerpt from the article by Gary Taubes:
Many explanations have been offered to make sense of the here-today-gone-tomorrow nature of medical wisdom — what we are advised with confidence one year is reversed the next — but the simplest one is that it is the natural rhythm of science. An observation leads to a hypothesis. The hypothesis (last year’s advice) is tested, and it fails this year’s test, which is always the most likely outcome in any scientific endeavor. There are, after all, an infinite number of wrong hypotheses for every right one, and so the odds are always against any particular hypothesis being true, no matter how obvious or vitally important it might seem.
You can access the New York Times article here.