There is a saying about surgeons, meant as a reproof: "Sometimes wrong; never in doubt." But this seemed to me their strength. Each day surgeons are faced with uncertainties. Information is inadequate; the science is ambiguous; one's knowledge and abilities are never perfect. Even with the simplest operation, it cannot be taken for granted that a patient will come through better off - or even alive. Standing at the table my first time, I wondered how the surgeon knew that he would do this patient good, that all the steps would go as planned, that the bleeding would be controlled and infection would not take hold and organs would not be injured. He didn't, of course. But still he cut.