On Separating Predictability and Determinism

There has been a long-standing debate about the relationshipof predictability and determinism. Some have maintained that determinism impliespredictability while others have maintained that predictability implies determinism. Manyhave maintained that there are no implication relations between determinism andpredictability. This summary is, of course, somewhat oversimplified and quick at least in thesense that there are various notions of determinism and predictability at work in thephilosophical literature. In this essay I will focus on what I take to be the Laplacean visionfor determinism and predictability. While many forms of predictability areinconsistent with this vision, I argue that a suitably restricted notion of predictability,consistent with the practice of physicists, is implied by the Laplacean notion of determinism.It is argued that limitations on predictability are of an in principle nature in the Appendix.