"The core distinguishing feature of Darwin's explanation - and what made it so revolutionary - was, instead, the after-the-fact logic of this mechanism. Where previously it seemed natural to assume that the process responsible for orderly function and adaptive design necessarily preceded their effects - as in Lamarck's view of functional use and disuse determining the evolution of future functions - Darwin showed that, in principle, antecedent 'testing' of functional responses by trial and error was unnecessary to achieve adaptive outcomes. The process that generated variant forms could be completely uncorrelated with the process that determined which variant forms were functionally superior to the others in a given environment. So long as the options with favorable outcomes were preferentially reproduced or retained and re-expressed in future contexts, it did not matter why or how they were generated."

Slots and Values
ref	p111
source	Unnamed