Article II: On Numerical Distinction

326. This is the question: whence sins which are contained within the same species receive numerical distinction or individuation. The difficulty of the matter arises from this, that moralists take an act morally; because, on the one hand, acts physically several and diverse can morally constitute only one sin, and because, on the other hand, an act physically one can be morally multiple and make several sins. To solve this question, authors commonly assign a double source of numerical distinction, or a double root, one on the part of the subject, the other on the part of the object; namely, on the part of the subject, the multiplicity of morally interrupted acts; but on the part of the object, the diversity of total objects.

It is clear that where in one act several sins specifically distinct are given, for example, against justice and charity, these are also multiplied numerically.