The EPR Experiment: A Prelude to Bohr’s Reply to EPR

Abstract

Bohr’s (1935) reply to Einstein, Podolsky, and Rosen’s (EPR’s) (1935) argument for the incompleteness of quantum theory is notoriously difficult to unravel. It is so diffcult, in fact, that over 60 years later, there remains important work to be done understanding it. Work by Fine (1986), Beller and Fine (1994), and Beller (1999) goes a long way towards correcting earlier misunderstandings of Bohr’s reply. This essay is intended as a contribution to the program of getting to the truth of the matter, both historically and philosophically. In a paper of this length, a full account of Bohr’s reply is impossible, and so I shall focus on one issue where it seems further clarification is required, namely, Bohr’s attempt to illustrate EPR’s argument by means of a thought experiment. In addition, I shall attempt to clarify a few other points which, however minor, have apparently contributed to misunderstandings of Bohr’s position. As the title of this paper suggests, an account of these few points does not constitute an account of Bohr’s reply, but it is an important step in that direction.

Thanks to audiences at Indiana University and HOPOS 2000 for comments on related talks. Thanks to Arthur Fine for alerting me to some secondary literature. Thanks to Michael Friedman and Scott Tanona for helpful discussions.