H. D. Zeh
postal address: Gaiberger Str. 38, D69151 Waldhilsbach, Germany
Received: 13 March 2006 / Accepted: 4 April 2006 / Published: 5 April 2006
Abstract: In a series of papers [1,2,3], Lawrence Schulman presented examples which demonstrate the compatibility of opposite arrows of time in various situations. In a previous letter to this journal  I questioned some of them for not being realistic in spite of being logically correct. Schulman replied  to these objections in a letter directly succeeding my one. I am here trying to clarify some aspects of the dispute, thereby further explaining and supporting my previous conclusions.
Keywords: time arrow; final conditions; solvable models; causality; retardation; quantum measurements; gravitational entropy; cosmology.