. On the other hand it has been urged that if the earth goes round
with the outer heaven and sun in twenty-four hours, there is no way of
accounting for the alternation of day and night; since the equal motion
of the earth and sun would have the effect of absolute immobility. To
which it may be replied that Plato never says that the earth goes round
with the outer heaven and sun; although the whole question depends on
the relation of earth and sun, their movements are nowhere precisely
described. But if we suppose, with Mr. Grote, that the diurnal rotation
of the earth on its axis and the revolution of the sun and outer heaven
precisely coincide, it would be difficult to imagine that Plato was
unaware of the consequence. For though he was ignorant of many things
which are familiar to us, and often confused in his ideas where we have
become clear, we have no right to attribute to him a childish want of
reasoning about very simple facts, or an inability to understand the
necessary and obvious deductions from geometrical figures or movements.
Of the causes of day and night the pre-Socratic philosophers, and
especially the Pythagoreans, gave various accounts, and therefore the
question can hardly be imagined to have escaped him. On the other hand
it may be urged that the further step, however simple and obvious, is
just what Plato often seems to be ignorant of, and that as there is
no limit to his insight, there is also no limit to the blindness which
sometimes obscures his intelligence (compare the construction of solids
out of surfaces in his account of the creation of the world, or the
attraction of similars to similars). Further, Mr. Grote supposes, not
that (Greek) means 'revolving,' or that this is the sense in which
Aristotle understood the word, but that the rotation of the earth is
necessarily implied in its adherence to the cosmical axis. But (a) if,
as Mr Grote assumes, Plato did not see that the rotation of the earth
on its axis and of the sun and outer heavens around the earth in equal
times was inconsistent with the alternation of day and night, neither
need we suppose that he would have seen the immobility of the earth to
be inconsistent with the rotation of the axis. And (b) what proof is
there that the axis of the world revolves at all? (c) The comparison of
the two passages quoted by Mr Grote (see his pamphlet on 'The Rotation
of the Earth') from Aristotle De Coelo, Book II (Greek) clearly shows,
although th