RAJENDRA PRASAb Causality and Quantum Mechanics MORE than ever before., science has become the determinative factor in assessing the validity or otherwise of philosophical views. Recent scientific discoveries are made use of by philosophers^ scientists and social scientists to buttress their own views of the nature of reality and man's place therein; of the process of acquiring knowledge and its limits, and so on. Belonging to the inamicable camps of idealism and materialism they seek support from the very same discoveries made in the micro-domain of physical reality. The popular interpretation of discoveries in the micro-domain is the Copenhagen Interpretation of quantum mechanics developed by scientists of positivist inclination who also contributed to the development of its basic formalism. According to this interpretation physics can no longer be regarded as the study of the physical world in the familiar sense but is concerned only with the ordering or structuring of observations. Laws of physics are viewed by these scientists as expressions of this ordering of observations and not of the intrinsic nature of physical reality existing independently of observation. It is also maintained by this school that the notion of causality can no longer be considered valid. Heisenberg's uncertainty relations., according to which it is not possible to determine the value of the conjugate variables of a micro-