ima ii, text. 37). Therefore in the angel to understand is to
exist.

Obj. 2: Further, cause bears the same relation to cause, as effect to
effect. But the form whereby the angel exists is the same as the form
by which he understands at least himself. Therefore in the angel to
understand is to exist.

_On the contrary,_ The angel's act of understanding is his movement,
as is clear from Dionysius (Div. Nom. iv). But to exist is not
movement. Therefore in the angel to be is not to understand.

_I answer that,_ The action of the angel, as also the action of any
creature, is not his existence. For as it is said (Metaph. ix, text.
16), there is a twofold class of action; one which passes out to
something beyond, and causes passion in it, as burning and cutting;
and another which does not pass outwards, but which remains within the
agent, as to feel, to understand, to will; by such actions nothing
outside is changed, but the whole action takes place within the agent.
It is quite clear regarding the first kind of action that it cannot be
the agent's very existence: because the agent's existence is signified
as within him, while such an action denotes something as issuing from
the agent into the thing done. But the second action of its own nature
has infinity, either simple or relative. As an example of simple
infinity, we have the act "to understand," of which the object is "the
true"; and the act "to will," of which the object is "the good"; each
of which is convertible with being; and so, to understand and to will,
of themselves, bear relation to all things, and each receives its
species from its object. But the act of sensation is relatively
infinite, for it bears relation to all sensible things; as sight does
to all things visible. Now the being of every creature is restricted
to one in genus and species; God's being alone is simply infinite,
comprehending all things in itself, as Dionysius says (Div. Nom. v).
Hence the Divine nature alone is its own act of understanding and its
own act of will.

Reply Obj. 1: Life is sometimes taken for the existence of the living
subject: sometimes also for a vital operation, that is, for one
whereby something is shown to be living. In this way the Philosopher
says that to understand is, in a sense, to live: for there he
distinguishes the various grades of living things according to the
various functions of life.

Reply Obj. 2: The essence of an angel is the reason of his entire
e