Introduction
The study of moral theology begins with a consideration of the ultimate end of man. Therefore, many problems in moral theology are solved by meditating on our ultimate end and on how our acts are ordered towards this end. In fact, we may extend this and be so bold as to affirm that every problem in moral theology is solved by such a consideration. The entire concatenation of the supernatural organism, which moral theology studies, is ordered towards, as St. Thomas notes, “the rational creature’s advance towards God,” who is the rational creature’s last end (ST I, q. 2, prol.).
This consideration of the end, and of how we are ordered towards it, is especially illuminating in solving the problems that arise in our consideration of sin, which is to be considered as the act that deviates from our ultimate end. In these notes, I hope to help the reader’s understanding of this on two points that are often difficult to grasp.
First, I will explain the distinction between the notions of imperfection, venial sin, and mortal sin from the perspective of how one may intend the ultimate end.
Second, I will explain, in light of the same, how we are to consider the problem of whether the unbeliever sins in all that he does (or, to the contrary, whether he may in certain deliberate acts be free from sin).
In my opinion, the teaching of certain heretics on these two points derives from the same root, namely their doctrine of the ultimate end, as does the distinction on these points wherein the schools differ from one another.
