uantity, so may it be
according to virtual quantity. Now increase in bodily quantity
results from addition; for the Philosopher says (De Gener. i, 5) that
"increase is addition to pre-existing magnitude." Therefore the
increase of charity which is according to virtual quantity is by
addition.

Obj. 2: Further, charity is a kind of spiritual light in the soul,
according to 1 John 2:10: "He that loveth his brother abideth in the
light." Now light increases in the air by addition; thus the light in
a house increases when another candle is lit. Therefore charity also
increases in the soul by addition.

Obj. 3: Further, the increase of charity is God's work, even as the
causing of it, according to 2 Cor. 9:10: "He will increase the growth
of the fruits of your justice." Now when God first infuses charity,
He puts something in the soul that was not there before. Therefore
also, when He increases charity, He puts something there which was
not there before. Therefore charity increases by addition.

_On the contrary,_ Charity is a simple form. Now nothing greater
results from the addition of one simple thing to another, as proved
in _Phys._ iii, text. 59, and _Metaph._ ii, 4. Therefore charity does
not increase by addition.

_I answer that,_ Every addition is of something to something else: so
that in every addition we must at least presuppose that the things
added together are distinct before the addition. Consequently if
charity be added to charity, the added charity must be presupposed as
distinct from charity to which it is added, not necessarily by a
distinction of reality, but at least by a distinction of thought. For
God is able to increase a bodily quantity by adding a magnitude which
did not exist before, but was created at that very moment; which
magnitude, though not pre-existent in reality, is nevertheless
capable of being distinguished from the quantity to which it is
added. Wherefore if charity be added to charity we must presuppose
the distinction, at least logical, of the one charity from the other.

Now distinction among forms is twofold: specific and numeric.
Specific distinction of habits follows diversity of objects, while
numeric distinction follows distinction of subjects. Consequently a
habit may receive increase through extending to objects to which it
did not extend before: thus the science of geometry increases in one
who acquires knowledge of geometrical matters which he ignored
hitherto. But th