The Times published two letters (Dec. 29) from creationists who objected to the Darwinian theory of evolution being taught as "truth" in the public schools. These letters display a common lack of understanding of what scientific truth is.
The theory of evolution by natural selection is almost as well confirmed by observation as the atomic theory or the theory of gravitation. To teach evolution as less "true" than these other theories is preposterous; it makes as much sense to teach biology without Darwin as to teach physics without Newton. On the other hand, people who are disturbed by evolution are free to consider it as just a convenient hypothesis, useful to doing biology, geology and medicine, or as God's way of working out his creation.
Science makes no pretensions to any Ultimate Truth. The truth of science is that of the practical man. A scientific theory makes predictions about future observations, and its truth is judged by how well its predictions are confirmed by experiment; science is essentially a sophisticated system for making bets. A theory is judged by its simplicity, by its power to explain, and of course by how well it is confirmed.
Many different theories may explain a given set of observations and no one be more "true" than another. For example, Newton's theory of gravitation predicts the motions of eight outer planets of our solar system to phenomenal accuracy (one part in 100 million). Is Newton's theory "true"? No, for it does not explain the orbit of Mercury if one observes Mercury with sufficient care for a sufficiently long period. Einstein's theory of gravitation, which does explain Mercury, is thus more "true" than Newton's, but Newton's is just as "true" if you are only interested in Jupiter.
