Locality and Determinism: The Odd Couple

Abstract

This paper examines the conceptual relations between the notions of determinism and locality. From a purely conceptual point of view, determinism does not appear to imply locality, nor (contrapositively) does nonlocality appear to imply indeterminism. The example of Newtonian mechanics strengthens this impression. It turns out, however, that in the context of quantum mechanics, a more complex connection between determinism and locality emerges. The connection becomes crucial when nonlocality is distinguished from no signaling. I argue that it is indeterminism that allows nonlocal theories such as quantum mechanics to comply with the no signaling constraint. I examine a number of interpretations of quantum mechanics, among them that of Schrödinger, Pitowsky and Popescu and Rohrlich, to support this claim.