compares these capital vices to the "leaders of an army."

Reply Obj. 1: The term "capital" is taken from _caput_ and applied to
something connected with, or partaking of the head, as having some
property thereof, but not as being the head taken literally. And
therefore the capital vices are not only those which have the
character of primary origin, as covetousness which is called the
"root," and pride which is called the beginning, but also those which
have the character of proximate origin in respect of several sins.

Reply Obj. 2: Sin lacks order in so far as it turns away from God,
for in this respect it is an evil, and evil, according to Augustine
(De Natura Boni iv), is "the privation of mode, species and order."
But in so far as sin implies a turning to something, it regards some
good: wherefore, in this respect, there can be order in sin.

Reply Obj. 3: This objection considers capital sin as so called from
the punishment it deserves, in which sense we are not taking it here.
________________________

FOURTH ARTICLE [I-II, Q. 84, Art. 4]

Whether the Seven Capital Vices Are Suitably Reckoned?

Objection 1: It would seem that we ought not to reckon seven capital
vices, viz. vainglory, envy, anger, sloth, covetousness, gluttony,
lust. For sins are opposed to virtues. But there are four principal
virtues, as stated above (Q. 61, A. 2). Therefore there are only four
principal or capital vices.

Obj. 2: Further, the passions of the soul are causes of sin, as
stated above (Q. 77). But there are four principal passions of the
soul; two of which, viz. hope and fear, are not mentioned among the
above sins, whereas certain vices are mentioned to which pleasure and
sadness belong, since pleasure belongs to gluttony and lust, and
sadness to sloth and envy. Therefore the principal sins are
unfittingly enumerated.

Obj. 3: Further, anger is not a principal passion. Therefore it
should not be placed among the principal vices.

Obj. 4: Further, just as covetousness or avarice is the root of sin,
so is pride the beginning of sin, as stated above (A. 2). But avarice
is reckoned to be one of the capital vices. Therefore pride also
should be placed among the capital vices.

Obj. 5: Further, some sins are committed which cannot be caused
through any of these: as, for instance, when one sins through
ignorance, or when one commits a sin with a good intention, e.g.
steals in order to give an alms. Therefore the capital vice