John Stachel

A discussion of the meaning of a physical concept cannot be separated from discussion of the conditions for its ideal measurement. We assert that quantization is no more than the invocation of the quantum of action in the explanation of some process or phenomenon, and does not imply an assertion of the fundamental nature of such a process. This leads to an ecumenical approach to the problem of quantization of the gravitational field. There can be many valid approaches, each of which should be judged by the domain of its applicability to various phenomena. If two approaches have overlapping domains, the relation between them then itself becomes a subject of study. We advocate an approach to general relativity based on the unimodular group, which emphasizes the physical significance and measurability of the conformal and projective structures. A discussion of the method of matched asymptotic expansions, and of the weakness of terrestrial sources compared with astrophysical and cosmological sources, leads us to suggest theoretical studies of gravitational radiation based on retrodiction rather than prediction

In three volumes, a distinguished group of scholars from a variety of disciplines in the natural and social sciences, the humanities and the arts contribute essays in honor of Robert S. Cohen, on the occasion of his 70th birthday. The range of the essays, as well as their originality, and their critical and historical depth, pay tribute to the extraordinary scope of Professor Cohen's intellectual interests, as a scientist-philosopher and a humanist, and also to his engagement in the world of social and political practice. In Science, Politics and Social Practice, (Volume II of Essays in Honor of Robert S. Cohen), an international group of scholars -- philosophers, sociologists, historians, and political scientists -- discuss issues at the cutting edge of contemporary social and political thought, and its bearing on science. Several essays discuss the relations of Marxism to science, and specifically, to the philosophies of science of Carnap and Popper, as well as Soviet Marxism, and the effects of Stalinism on Soviet science. There are also essays on the philosophy and methodology of the social sciences, on questions of method and aim in historical narrative, on the issue of cultural relativism, and more.