Abstract
It was C.H. Waddington's contention that the Neo-Darwinian Theory of Evolution ought to be amended by imbedding it in a broader theoretical framework which takes the role of the phenotype into account. Waddington's theory alleges the existence of two interlocking feedback circuits between environment and phenotype on the one hand and genotype and phenotype on the other. The resulting dynamical model of evolutionary change gives new meaning to the notion of progress in evolution. In this model natural selection acts directly on the phenotype, thereby influencing the feedback relationships. Better tuning of the feedback relations, however, leads to progress in adaptability which in Waddington's theory replaces the cumbersome concept of progress in adaptation.This paper expounds Waddington's theory and places it into a broader philosophical perspective.