Evolutionary Randomness

Abstract Contemporary defenses of the randomness doctrine refer not to ordinary meanings of randomness, but to a special evolutionary meaning by which mutation is said to be independent of, or uncorrelated with, something like environment, selection, evolution, or adaptation. Chapter 4 addresses whether this type of claim is justified, either empirically or on the basis of principles of biology. In fact, claims of evolutionary randomness typically fail for obvious reasons. Mutation in a particular locale is not walled off from the rest of biology, but is sensitive to conditions such as gene expression and the concentration of DNA precursors, and this leads to nonindependence with conditions and even with fitness. The incipient fitness effects of mutational intermediates typically are not involved in feedback loops that enhance (diminish) the chances of completing a beneficial (harmful) mutation, but this narrow sense of independence has little practical value.