o be sterile. Hence the Ideas have within
themselves no principle for the production of things, and the
scientific explanation of things by this means becomes impossible.
Hence there is nothing for it but to have recourse to myth. Plato can
only imagine that things are produced by a world-former, or designer,
who, like a human artist, fashions the plastic matter into images of
the Ideas.

God, the Creator, the world-designer, finds beside him, on the one
hand, the Ideas, on the other, formless matter. First, he creates the
World-Soul. This is incorporeal, but occupies space. He spreads it out
like a huge net in empty space. He bisects it, and bends the two
halves into an inner and an outer circle, these circles being destined
to become the spheres of the planets and the stars respectively. He
takes matter and binds it into the four elements, and these elements
he builds into the empty framework of the World-Soul. When this is
done, the creation of the universe is complete. The rest of the
"Timaeus" is occupied with the details of Plato's ideas of astronomy
and physical {211} science. These are mostly worthless and tedious,
and we need not pursue them here. But we may mention that Plato, of
course, regarded the earth as the centre of the world. The stars,
which are divine beings, revolve around it. They necessarily move in
circles, because the circle is the perfect figure. The stars, being
divine, are governed solely by reason, and their movement must
therefore be circular, because a circular motion is the motion of
reason.

The above account of the origin of the world is merely myth, and Plato
knows that it is myth. What he apparently did believe in, however, was
the existence of the World-Soul, and a few words upon this subject are
necessary. The soul, in Plato's system, is the mediator between the
world of Ideas and the world of sense. Like the former, it is
incorporeal and immortal. Like the latter, it occupies space. Plato
thought that there must be a soul in the world to account for the
rational behaviour of things, and to explain motion. The reason which
governs and directs the world dwells in the World-Soul. And the
World-Soul is the cause of motion in the outer universe, just as the
human soul is the cause of the motions of the human body. The cosmos
is a living being.

_(b) The Doctrine of the Human Soul_.

The human soul is similar in kind to the World-Soul. It is the cause
of the body's movements, a