More on the Arrow of Time

Abstract

A basic time asymmetry is said to exist in the conventional quantum theory of measurement because the initial state, determined by the initial measurement, suffers a reduction of the wave packet when a succeeding measurement is made. It is shown, completely within the conventional framework, that the sense of this time asymmetry can be reversed and a retroductive formalism introduced which is based upon the fact that only the final state is known. Moreover, if both the initial and final states of a set of measurements are fixed, a completely time symmetric formalism can be constructed for the time interval between these given states. The selection of the predictive scheme can be made with the help of macroscopic considerations and consequently it appears that the basic time asymmetry is not a consequence of conventional quantum physics including measurement.