In that stochastic system to which Darwinians have paid most attention, the random component is genetic change, either by mutation or by the reshuffling of genes among members of a population. I assume mutation to be nonresponsive to environmental demand or to internal stress of the organism. I assume, however, that the machinery of selection which acts on the randomly varying organisms will include both each creature’s internal stress and, later, the environmental circumstances to which the creature is subjected.
— Bateson, Gregory. Mind and Nature. A Necessary Unity. New York: E. P. Dutton, 1979.
