Physics 155
and hearsay that some divine force and godly power existed; and then
one day the earth opened its maw and they could emerge from those
hidden places and come out into the regions which we inhabit, and they
then became aware of the huge clouds and the force of the winds and
saw the sun in all its great size and beauty, and also became aware of its
creative power (for it created the day by spreading its light throughout
the entire heaven); and then when night darkened the earth they could
see the whole heaven adorned and ornamented with stars, and the changes
in the illumination of the moon as it waxed and waned, and the risings
and settings of all those heavenly bodies moving in courses immutably
fixed for all of eternity-when they saw all of this, certainly they would
think that both that there are gods and that these things are their handi-
work."
115 .... And not only are these things amazing, but there is nothing
more so than the fact that the cosmos is so stable and so internally
coherent that nothing can even be conceived of which is more suited to
permanent existence. For all of its parts from every direction exert an
equal effort to reach the centre. Moreover, compound bodies maintain
their existence most effectively when they are surrounded by a kind of
bond which ties them together; and this is done by that nature which
penetrates the entire cosmos and causes everything with its intelligence
and rationality, rapidly drawing the outermost parts [of the cosmos] back
towards the centre. 116. So if the cosmos is spherical, and as a result all
its parts from every direction are held together in an equal balance by
each other and with each other, then it is necessary that the same thing
must apply to the earth too; consequently, since all the parts of the earth
tend towards the centre (and the centre is the lowest point in a sphere),
there is no break in its continuity which might cause such a large and
coordinated system of weight and gravity to crumble. And similarly the
sea, which lies above the earth and yet strives to reach the centre of the
earth, is evenly balanced on all sides and so forms a sphere; it never
overflows or exceeds its bounds. 117. Air is continuous with the sea and
is borne aloft by its lightness; but still it distributes itself in all directions;
and so it is both continuous with the sea and joined to it, and by nature
it moves upwards to the heavens, whose rareness and heat blend with it
and so enable the air to provide to animals life-giving and beneficial
pneuma. The highest part of the heaven, which is termed aitherial, em-
braces the air and also retains its own rarefied heat, being compounded
with nothing else, and [yet] it is conjoined with the boundaries of the
air. And the heavenly bodies revolve in the aither; by their own effort
they hold themselves together in their spherical shape, and in virtue of
their shape and form they sustain their movements-for they are round