In this volume which was originally published in 1982 Paul Horwich presents a clear and unified approach to a number of problems in the philosophy of science. He diagnoses the failure of other attempts to resolve them as stemming from a too-rigid all-or-nothing conception of belief and adopts instead a Bayesian strategy emphasising the degree of confidence to which we are entitled the light of scientific evidence. This probabilistic approach he argues yields a more complete understanding of the assumptions and procedures characteristic of scientific reasoning. It also accounts for the merits of simplicity severe tests and surprising predictions and provides a way in which the dispute between the realist and instrumentalist views of science might be resolved. The result is a crisp well-focused contribution to the philosophy of science. The elaboration of an important conception of probability will stimulate anyone with an interest in the field. Language: English