There may or may not be a correlation between the beautiful and the good, but there probably is one between beauty and health. (Which, I suppose, in Darwinian terms, is the good.) Evolutionary biologists believe that in many creatures beauty is a reliable indicator of health, and therefore a perfectly sensible way to choose one mate over another. Gorgeous plumage, lustrous hair, symmetrical features are “certificates of health,” as one scientist puts it, advertisements that a creature carries genes for resistance to parasites* and is not otherwise under stress.