Einstein's Revolution: A Case Study in Communicative Rationality.

The aim of the paper is to demonstrate that Special Relativity and the Early Quantum Theory were created within the same programme of statistical mechanics, thermodynamics and maxwellian electrodynamics reconciliation. I shall try to explain why classical mechanics and classical electrodynamics were ``refuted'' almost simultaneously or, in more suitable terms for the present congress, why did the quantum revolution and the relativistic one both took place at the beginning of the 20-th century. I shall argue that the quantum and relativistic revolutions were simultaneous since they had a common origin -- the clash between the fundamental theories of the second half of the 19-th century that constituted the ``body'' of Classical Physics. The revolution's most dramatic point was Einstein's 1905 photon paper that laid the foundations of both Special Relativity and Old Quantum Theory. Hence the dialectic of the old theories is crucial for theory change. Modern physics began with Einstein's reconciliation of electrodynamics, mechanics and thermodynamics in 1905 and his unification of Special Relativity and Newtonian Theory of Gravity. Or, in a more general social context: progressive scientific change can be described not in Weberian terms of zweckrational action forcing out all the other forms of action only but in terms of Habermas's communicative rationality encouraging the establishment of mutual understanding between the various scientific communities also. Einstein's programme constituted a progressive step with respect to its rivals not because it could explain more ``facts'' or was more ``mathematical''. It was better than its rivals because it constituted a basis of communication and interpenetration between three main paradigms of 19-th century physics. Of course in the long run it resulted in empirical successes. [ABSTRACT FROM AUTHOR]