Abstract

Some brief remarks are made on the relation between the ordering and dimensionality properties of time and the laws of physics. Time is defined as the ordinal of the set of photographs describing the configuration of the Universe associated with each collision of a test particle. This set of pictures is ordered by a parameter which appears in simple physical laws, and it is these laws which determine the ordering. Time is one-dimensional because these snapshots can be ordered with a single parameter. The signature of space-time appears to be related to the measurement process. If there were no time dimension, there would probably be no physical laws, because there would seem to be nothing to predict: while if there were more than one timelike dimension, then the extra dimensions may be unobservable and so physically nonexistent