Page:Early Greek philosophy by John Burnet, 3rd edition, 1920.djvu/315

Rh revolution. It was probably this that led to the abandonment of the theory.

In discussing the views of those who hold the earth to be in motion, Aristotle only mentions one theory as alternative to that of its revolution round the central fire, and he says that it is that of the Timaeus. According to this the earth is not one of the planets but "at the centre," while at the same time it has some kind of motion relatively to the axis of the universe. Now this motion can hardly be an axial rotation, as was held by Grote; for the whole cosmology of the Timaeus implies that the alternation of day and night is due to the diurnal revolution of the heavens. The fact that the earth is referred to a little later as "the guardian and artificer of night and day" proves nothing to the contrary, since night is in any case the conical shadow of the earth, which is thus the cause of the alternation of day and night. So far, Boeckh and his followers appear to be in the right.