Chemistry guides evolution, claims theory
That enduring metaphor for the randomness of evolution, a blind watchmaker that works to no pattern or design, is being challenged by two European chemists. They say that the watchmaker may have been blind, but was guided and constrained by the changing chemistry of the environment, with many inevitable results.
An action can be both random and constrained: a standard dice is random, but it is constrained to integers between 1 and 6... It will never roll a 3½. Evolution is constrained by both physical laws and history.