Last summer, at a meeting outside Aspen, Colorado, several dozen physicists gathered to celebrate what the journal Nature described as the "growing feeling that their discipline's mindset will be crucial to reaping the harvest of biology's post-genomic era." In fact, with genetics set to improve everything from human health to agriculture, physicists and mathematicians worldwide are pouring into the life sciences. Biology is where the scientific action--and the money--will be in the coming century.
But this is not the first time that physicists and mathematicians have looked to biology for new fields to plow, and the history of such efforts has been fairly dismal. Biologists and physicists have different goals and traditions, and they look for different kinds of answers, because they ask different kinds of questions.
My first glimpse of this disciplinary divide came many years ago while teaching a course on mathematical methods in biology. After introducing a biological problem with 11 variables, I used a simple method called dimensional analysis to demonstrate that only three needed to be studied empirically; the relations among the rest of the variables could be inferred logically. "But you haven't done the experiments," the students complained, "so how can you know?"
I've been thinking about that question ever since. As a theoretical physicist, I had been trained to trust only mathematical and logical arguments and to view experimental evidence as fallible. But to many, if not most, biologists, experimental evidence, however fallible, still provided a surer path to truth. Where, in a purely deductive argument, was there room for nature's surprises, for mechanisms that look nothing like what we imagine in our initial assumptions?