its acts, powers, and nature, down to the minutest
details, whereas he who knows a thing in an imperfect manner can only
distinguish it in a general way, and only as regards a few points.
Thus, one who knows natural things imperfectly, can distinguish their
orders in a general way, placing the heavenly bodies in one order,
inanimate inferior bodies in another, plants in another, and animals
in another; whilst he who knows natural things perfectly, is able to
distinguish different orders in the heavenly bodies themselves, and
in each of the other orders.

Now our knowledge of the angels is imperfect, as Dionysius says (Coel.
Hier. vi). Hence we can only distinguish the angelic offices and
orders in a general way, so as to place many angels in one order. But
if we knew the offices and distinctions of the angels perfectly, we
should know perfectly that each angel has his own office and his own
order among things, and much more so than any star, though this be
hidden from us.

Reply Obj. 1: All the angels of one order are in some way equal in a
common similitude, whereby they are placed in that order; but
absolutely speaking they are not equal. Hence Dionysius says (Coel.
Hier. x) that in one and the same order of angels there are those who
are first, middle, and last.

Reply Obj. 2: That special distinction of orders and offices wherein
each angel has his own office and order, is hidden from us.

Reply Obj. 3: As in a surface which is partly white and partly black,
the two parts on the borders of white and black are more akin as
regards their position than any other two white parts, but are less
akin in quality; so two angels who are on the boundary of two orders
are more akin in propinquity of nature than one of them is akin to
the others of its own order, but less akin in their fitness for
similar offices, which fitness, indeed, extends to a definite limit.
_______________________

FOURTH ARTICLE [I, Q. 108, Art. 4]

Whether the Distinction of Hierarchies and Orders Comes from the
Angelic Nature?

Objection 1: It would seem that the distinction of hierarchies and of
orders is not from the nature of the angels. For hierarchy is "a
sacred principality," and Dionysius places in its definition that it
"approaches a resemblance to God, as far as may be" (Coel. Hier. iii).
But sanctity and resemblance to God is in the angels by grace, and not
by nature. Therefore the distinction of hierarchies and orders in the
angel