9. Let us now examine how it happens that the soul descends into
the body, and in what manner this occurs; for it is sufficiently
astonishing and remarkable. For a soul, there are two kinds of entrance
into a body. The first occurs when the soul, already dwelling in a
body, undergoes a transmigration; that is, passes from an aerial or
igneous body into a terrestrial body. This is not usually called a
transmigration, because the condition from which the soul comes is not
visible. The other kind occurs when the soul passes from an incorporeal
condition into any kind of a body, and thus for the first time enters
into relations with a body.[116]