ELTE TTK Tudomanytortenet es Tudomanyfilozofia Tanszek Budapest, Pazmany P. setany 1/A TUDOMANYFILOZOFIA SZEMINARIUM (http://hps.elte.hu/~leszabo/szeminar/folap.htm) ________________________________________________ 1999. Szeptember 27. (hetfo !) 12:30 6. em. 661. B a r r y L o e w e r Rutgers University Collegium Budapest PROBABILITY AND DETERMINISM Although probability is essential to the formulation (and evaluation) of scientific theories and although a great deal is known about how to employ probabilistic concepts, there is still philosophical controversy concerning the nature of probability. Some hold that only probability concerns only degrees of belief (either subjective or constrained by "objective" rules) while others hold that it concerns mind-independent features of reality. The latter view divides among those who hold that it concerns only frequencies (actual or hypothetical) and those who hold that it concerns a "causal propensity." The nature of probability is especially puzzling when the underlying dynamics is completely deterministic as in classical mechanics and Bohm's version of quantum mechanics. Some claim that when the dynamics is deterministic then all objective probabilities are 1 or 0. But this seems at odd with the scientific practice. In my talk I will review some of the main ideas concerning the nature of probability and also an idea suggested by David Lewis. According to Lewis probability concerns an objective feature of reality that supervenes on the totality of propositions not concerning chance. Whether or not Lewis' account is correct for dynamical chances I argue that it provides a good account of chance statements when the dynamics are deterministic. -- Laszlo E. Szabo Department of Theoretical Physics Department of History and Philosophy of Science Eotvos University, Budapest H-1518 Budapest, Pf. 32. Phone: (36-1)2090-555/6671 Fax: (36-1)372-2509 Home: (36-1)200-7318 http://hps.elte.hu/~leszabo