On The Soul
but of that which has mind, so far as it has it. That is why, when
this vehicle decays, memory and love cease; they were activities not
of mind, but of the composite which has perished; mind is, no doubt,
something more divine and impassible. That the soul cannot be moved is
therefore clear from what we have said, and if it cannot be moved at
all, manifestly it cannot be moved by itself.
Of all the opinions we have enumerated, by far the most unreasonable
is that which declares the soul to be a self-moving number; it
involves in the first place all the impossibilities which follow
from regarding the soul as moved, and in the second special
absurdities which follow from calling it a number. How we to imagine a
unit being moved? By what agency? What sort of movement can be
attributed to what is without parts or internal differences? If the
unit is both originative of movement and itself capable of being
moved, it must contain difference.
Further, since they say a moving line generates a surface and a
moving point a line, the movements of the psychic units must be
lines (for a point is a unit having position, and the number of the
soul is, of course, somewhere and has position).
Again, if from a number a number or a unit is subtracted, the
remainder is another number; but plants and many animals when
divided continue to live, and each segment is thought to retain the
same kind of soul.
It must be all the same whether we speak of units or corpuscles; for
if the spherical atoms of Democritus became points, nothing being
retained but their being a quantum, there must remain in each a moving
and a moved part, just as there is in what is continuous; what happens
has nothing to do with the size of the atoms, it depends solely upon
their being a quantum. That is why there must be something to
originate movement in the units. If in the animal what originates
movement is the soul, so also must it be in the case of the number, so
that not the mover and the moved together, but the mover only, will be