We are in the process of a profound change in our model of medicine. The change is, or seems to be, taking place so fast that it may be useful now to take a step back to look at some of the reasons why medicine resists change and some of the forces that may now be compelling it.

Medicine is based on science -- on the biology, chemistry, and physics that every pre-medical student has to pass -- and is embedded in its world view, constricted by its conventions, reinforced by the kinds of social structures and economic interests which sustain and shape science. But it is also quite different and special. The successes, limitations, and failures of medicine have a felt immediacy that is simply missing from geology, astronomy, or physics. Doctor's decisions, procedures, and medications are, literally, a matter of life and death -- for all of us. And so too, by extension, are the theories they are based on.

We have a passionate attachment to the achievements of our medicine and a desperate fear of its failures. On the one hand, we are terribly eager to believe in the science that promises to save our lives or relieve our misery, and in the health care professionals who bring us its benefits. On the other hand, when that science and those who serve it fail us, we have the most powerful incentive to look for help from alternatives which may call every aspect of that "conventional medicine" into question. As more and more of us gain more and more access to information about the latest developments in medicine both the possibilities for reinforcing the power of the existing system and the potential for challenging it increase.

During the last century the extraordinary benefits of biomedicine gave us both concrete help and an almost indomitable hope. Can't vaccines and antibiotics prevent and conquer once deadly infections -- smallpox and polio, meningitis, and rheumatic fever? Didn't our medical scientists isolate and synthesize the insulin that enables diabetics, once among the early dead, to live long and productive lives? Surgery and chemotherapy shrink and obliterate some tumors. Premature infants who would never have survived live. And now we wonder if inherited diseases that were thought years, or even months, ago to be beyond our therapeutic reach, might be cured by microsurgical genetic splices. At moments I suspect that even the most skeptical of us secretly hopes and feels that all illness may eventually yield to our relentless research effort.

For all their promise, however, our successes have had a conservative character. As a society we want innovation and progress, but for years the only change that most of us conceived of was that which took place within the bounds of the present scientific model: a new drug or procedure. We worried that if we changed our ways of research, or decreased its budget, or refused to go the extra investigational or therapeutic mile, something terrible might happen. Chemotherapy is not nearly so successful in treating cancer as we once hoped and anti-inflammatory drugs address symptoms, not causes, yet we have continued to invest billions in them and have kept on hoping. The terrible fear was that if we did not, we might omit that drug or fail to make that advance which could save our life or the life of someone we love.