moderate proportion and equal or only slightly unequal, they are really
mingled and tempered by the qualities which are in moderate relation to
each other. This indeed takes place in bodies but not in all bodies, but
only in those, as has been said, which are capable of reciprocal action
and influence and have the same matter subject to their qualities. For
all bodies which subsist in conditions of birth and decay seem to
possess a common matter, but all bodies are not capable of reciprocal
action and influence. But corporeals cannot in any way be changed into
incorporeals because they do not share in any common underlying matter
which can be changed into this or that thing by taking on its qualities.
For the nature of no incorporeal substance rests upon a material basis;
but there is no body that has not matter as a substrate. Since this is
so, and since not even those things which naturally have a common matter
can pass over into each other unless they have the power of acting on
each other and being acted upon by each other, far more will those
things not suffer interchange which not only have no common matter but
are different in substance, since one of them, being body, rests on a
basis of matter, while the other, being incorporeal, cannot possibly
stand in need of a material substrate.

It is therefore impossible for a body to be changed into an incorporeal
species, nor will it ever be possible for incorporeals to be changed
into each other by any process of mingling. For things which have no
common matter cannot be changed and converted one into another. But
incorporeal things have no matter; they can never, therefore, be changed
about among themselves. But the soul and God are rightly believed to be
incorporeal substances; therefore the human soul has not been converted
into the Godhead by which it was assumed. But if neither body nor soul
can be turned into Godhead, it could not possibly happen that manhood
should be transformed into God. But it is much less credible that the
two should be confounded together since neither can incorporality pass
over to body, nor again, contrariwise, can body pass over into
incorporality when these have no common matter underlying them which can
be converted by the qualities of one of two substances.

But the Eutychians say that Christ consists indeed of two natures, but
not in two natures, meaning, no doubt, th