||Operationalism is the view that the meaning of scientific concepts is to be given in terms of the operations which govern the application of such concepts. The principal advocate of operationalism was the Nobel-prize winning physicist Percy Bridgman (1882-1961) who developed the approach primarily with respect to physical concepts, such as length, space and time. Outside physics, operationalism had some influence in the development of behavioural psychology. With its emphasis on the operations employed in the application of a concept, operationalism resembles the logical positivist's verificationist view of meaning, though it focuses on the meaning of individual words rather than sentences. Now widely rejected, one of the main problems with operationalism is that the use of different operations for measuring the same magnitude generates different concepts, so that no unified concept of a magnitude exists if multiple means of measuring the magnitude exist.