The Time-symmetric Gold Universe Reconsidered

ABSTRACT

The present article proposes to re-examine the parity-of-reasoning or double-standard fallacy argument, which favours a time-symmetric Gold universe model over a cosmological arrow of time. There are two reasons for this re-examination. One is empirical: the recent discovery of an expanding and accelerating universe questions the symmetry assumption of the Gold universe on empirical grounds. The other is theoretical: the argument from t-symmetry fails to take into account some important aspects of the topology of phase space and recently developed typicality arguments. If the parity-of-reasoning argument, which depends on the t-symmetry of probability, is reconsidered in terms of the topology of phase space and typicality arguments, the double-standard fallacy argument loses much of its appeal. The Gold universe model itself suffers from unexplained dynamic asymmetries. The upshot of this article is that the Gold universe model is implausible or far less plausible than asymmetric models.

Notes

1 The converse does not hold: to one particular microstate there corresponds exactly one macrostate, which can be regarded as a snapshot of the microstates that make up a particular macrostate at a moment in time. As a macrostate, like temperature T, is defined as mean molecular kinetic energy, many particular configurations of the microstates can constitute the particular macrostate T.