w all these divisions refer
to the causes of sins. Therefore, seemingly, sins differ specifically
according to the diversity of their causes.

_On the contrary,_ If this were the case all sins would belong to one
species, since they are due to one cause. For it is written (Ecclus.
10:15) that "pride is the beginning of all sin," and (1 Tim. 6:10)
that "the desire of money is the root of all evils." Now it is
evident that there are various species of sins. Therefore sins do not
differ specifically according to their different causes.

_I answer that,_ Since there are four kinds of causes, they are
attributed to various things in various ways. Because the _formal_
and the _material_ cause regard properly the substance of a thing;
and consequently substances differ in respect of their matter and
form, both in species and in genus. The _agent_ and the _end_ regard
directly movement and operation: wherefore movements and operations
differ specifically in respect of these causes; in different ways,
however, because the natural active principles are always determined
to the same acts; so that the different species of natural acts are
taken not only from the objects, which are the ends or terms of those
acts, but also from their active principles: thus heating and cooling
are specifically distinct with reference to hot and cold. On the
other hand, the active principles in voluntary acts, such as the acts
of sins, are not determined, of necessity, to one act, and
consequently from one active or motive principle, diverse species of
sins can proceed: thus from fear engendering false humility man may
proceed to theft, or murder, or to neglect the flock committed to his
care; and these same things may proceed from love enkindling to undue
ardor. Hence it is evident that sins do not differ specifically
according to their various active or motive causes, but only in
respect of diversity in the final cause, which is the end and object
of the will. For it has been shown above (Q. 1, A. 3; Q. 18, AA. 4,
6) that human acts take their species from the end.

Reply Obj. 1: The active principles in voluntary acts, not being
determined to one act, do not suffice for the production of human
acts, unless the will be determined to one by the intention of the
end, as the Philosopher proves (Metaph. ix, text. 15, 16), and
consequently sin derives both its being and its species from the end.

Reply Obj. 2: Objects, in relation to external acts,