On The Soul
another), opinion the number of the plane, sensation the number of the
solid; the numbers are by him expressly identified with the Forms
themselves or principles, and are formed out of the elements; now
things are apprehended either by mind or science or opinion or
sensation, and these same numbers are the Forms of things.
Some thinkers, accepting both premisses, viz. that the soul is
both originative of movement and cognitive, have compounded it of both
and declared the soul to be a self-moving number.
As to the nature and number of the first principles opinions differ.
The difference is greatest between those who regard them as
corporeal and those who regard them as incorporeal, and from both
dissent those who make a blend and draw their principles from both
sources. The number of principles is also in dispute; some admit one
only, others assert several. There is a consequent diversity in
their several accounts of soul; they assume, naturally enough, that
what is in its own nature originative of movement must be among what
is primordial. That has led some to regard it as fire, for fire is the
subtlest of the elements and nearest to incorporeality; further, in
the most primary sense, fire both is moved and originates movement
in all the others.
Democritus has expressed himself more ingeniously than the rest on
the grounds for ascribing each of these two characters to soul; soul
and mind are, he says, one and the same thing, and this thing must
be one of the primary and indivisible bodies, and its power of
originating movement must be due to its fineness of grain and the
shape of its atoms; he says that of all the shapes the spherical is
the most mobile, and that this is the shape of the particles of fire
Anaxagoras, as we said above, seems to distinguish between soul
and mind, but in practice he treats them as a single substance, except
that it is mind that he specially posits as the principle of all
things; at any rate what he says is that mind alone of all that is