RICHARD HEALEY QUANTUM REALISM: NA?VET? IS NO EXCU 1. INTRODUCTION The purpose of this paper is to present as clearly as possible what I take to be the strongest currently available objections to a particularly simple and inviting form of quantum mechanical realism. Though they are the strongest, these are not the only objections available. Perhaps their presentation will convince philosophers, as many physicists have long been convinced, that this simple realistic approach is misguided. However, the long and controversial history of the ap proach suggests otherwise. 2. REALISM The form of quantum mechanical realism at the center of attentio here may reasonably be associated with the names of Popper and Einstein, amongst others.1 It pictures quantum mechanics as a stat tical theory of an objective, determinate domain. Whether or not tha domain is describable by a deterministic theory, it is held tha quantum mechanics gives only an indeterministic description of it The quantum domain is held to be determinate in that measurab quantities always possess definite values on any quantum system. It is held to be objective in that measurement is construed as merely ou way of getting to know what some of these values are. The theory is statistical, on this view, because in even the most favorable circum stances there are measurable quantities whose values on a give system at a given time are not derivable from the appropriate quantu mechanical description of the system at that time, while this descrip tion does yield probability distributions over sets of distinct values. I is indeterministic because no description of a quantum system at one time suffices within quantum mechanics to yield a unique value fo each measurable quantity on that system at another time. Because of its simplicity and initial attractiveness, this may be Synthese 42 (1979) 121-144. 0039-7857/79/0421-0121 $02.40. Copyright ? 1979 by D. Reidel Publishing Co., Dordrecht, Holland, and Boston, U.S.A This content downloaded from 150.135.239.97 on Wed, 07 Sep 2016 13:58:21 UTC All use subject to http://about.jstor.org/terms