First Question: On the Interior Causes of Sin

St. Thomas, I-II, q. 75, a. 1 and 2; De Malo, q. 1, a. 3.

461. In what way sin has a cause. - Sin 1) on the part of the act (the material element), has, like any act and any being, an efficient cause per se, namely, the power of man, especially the will insofar as it intends some created good; 2) on the part of disorder (the formal element), it has a cause in the mode in which negation can have a cause:

a) an efficient cause per accidens: for upon the placing of one effect there follows the absence of another; and thus a cause intending the placing is, per accidens, the cause of the consequent negation, as fire by causing heat consequently causes the privation of coldness. Thus the will intending a created good opposed to law at the same time produces the privation of conformity with law annexed to this good, which nevertheless it does not intend, but which it causes consequently, per accidens, and outside its intention. Whence the cause of sin per se on the part of the act is also per accidens the cause of disorder;

b) it has a deficient cause: for in sin there is not mere negation but privation; but that which ought to be in some effect would never be absent except on account of the defect of some cause. Therefore the will causes sin insofar as it defects from the direction of the rule of reason and the law of God, that is, insofar as it does not attend to it or does not use it. Nor is this defect or lack of the rule already sin (although it is a physical imperfection), but rather that the will proceeds with this lack to choosing and acting.

462. Sin has four interior causes on the part of the act: two proximate and immediate, reason and will, which are required in every sin; two remote and mediate, sensitive cognition and the appetite following, when sin is concerned with sensible good. In this case the imagination begins (at least ordinarily) and proposes a delectable good to the sensitive appetite, and immediately by that very fact the appetite is moved into it, preceding reason and enticing it to approve it and judge it good. Then reason adverts to the various advantages and disadvantages of this delectable good, even that it is or perhaps is against the law of God. Nevertheless reason, defecting from the rule, can approve it: then the will, by consenting to it, completes and perfects (through delight, through desire, or through the work) the notion of sin (James I, 14-15).

463. Division of the question. - Therefore sin is from reason directing badly, from appetite inclining under the guidance of imagination, and from will perfecting. Hence we shall speak:

1. of ignorance, which is the cause of sin on the part of reason;

2. of infirmity or passion, which is the cause of sin on the part of the sensitive appetite;

3. of malice (or contempt), which is the cause of sin on the part of the will.

Thus according to that saying of Isidore, De Summo Bono, book 2: "In three modes sin is carried on, that is, by ignorance, infirmity, and industry." Namely, sins are called sins of ignorance, infirmity, or malice, according as their principal cause or principle of sinning is ignorance, passion, or malice.

1. This distinction, however, is not essential and specific, but merely accidental of gravity, because it is not from the object. Therefore the same sin, for example, of homicide, can be from ignorance, passion, or malice.