Kuhn, 1962

The early developmental stages of most sciences have been characterized by continual number of distinct views in nature, each partially derived from, and all roughly compatible with, the dictates of scientific observation method. What differentiated those variance schools was not one or other failure of method-they were all scientific-but we shall come to call their incommensurable ways of seeing the world and of practicing science in it. Observation and experience can and must drastically restrict the range of admissible scientific belief, else there would be no science. But they cannot alone determine a particular body of such belief. An apparently arbitrary element, compounded of personal and historical accident, is always a formative ingredients of the belief espoused by scientific community at a given time.