Science, as Rachel Carson observed, is a part of the very fabric of life. It has its strengths and weaknesses, its successes and failures, its doubts and uncertainties. As scientists attempt to understand how a cell malfunctions to produce cancer, how a gene transmits information to guide an organism's development, how an ecosystem responds to urban sprawl, or how the entire Earth responds to long-term changes in the chemistry of its atmosphere, these investigations are enveloped with uncertainty at every stage. The uncertainty arises in many ways, and the nature of the uncertainty may change through time, but the scientific endeavor is never free of uncertainty.

Has science been debilitated by uncertainty? To the contrary, the successes of science, and indeed there are many, arise from the ways that scientists have learned to make use of uncertainty in their quests for knowledge.