Furthermore, it will be seen that the cylindrical universe introduces a species of absolute time, and this again has been used as an argument against its acceptance. But it should be noticed that this absolute time appears only when we view the universe as a whole. For ordinary problems restricted to smaller areas, the fusion of space and time remains complete, as before.
It is, of course, apparent that by changing the boundary conditions, as Einstein has done, by substituting a cylindrical universe for the quasi-Euclidean one, the gravitational equations will be somewhat modified. They will no longer be those which yielded the double bending of a ray of light. For now the additional
term will be included in their expression; though, so far as the planetary motions are concerned, the presence of this additional term will not modify our results. In de Sitter’s universe this introduction of the foreign magnitude
into the law of gravitation was somewhat unsatisfactory, marring the simple beauty of the equations;
was some independent constant posited by the Creator. The same argument could scarcely be directed against Einstein’s equations; for it should be remembered that if, as Einstein suggests,
is to be attributed to the matter of the universe, the circle is closed, since indirectly, at least, nothing but matter enters into the law of gravitation. According to this view, we might say that the total amount of matter in the universe conspired to create a gigantic law of gravitation. It is, then, under the cumulative action of matter that rays of light and free bodies describe circles.