Summa Theologiae Moralis, vol. I: De Principiis

S. Th. I-II, q. 85; 109, a. 7; De Malo q. 2, a. 11 and 12.

515. The first effect of sin is the diminution or corruption of the good of nature, not indeed of the principles by which human nature is constituted and of the properties which flow from them (as e.g. intellect and will), but of the natural inclination to virtue¹. For:

1. On the part of privation: by mortal sin (and therefore by original [sin]) man is turned away from the last end, whence the powers of the soul are deprived of due subordination to one another and to God, and so are deprived of due order to the good of virtue and negatively do not attain to their term. This subordination in the state of pure nature would have been imperfect from this, that, reason ordering, the will would convert itself to the last end God, and so by one act would habitually subject all the powers of man to itself and refer them to God; in the state of innocence however it was perfect through the supernatural gifts of original justice. Hence by original sin which takes away original justice, man is also said to be wounded in natural things, because in him all the powers of the soul remain deprived of that proper order by which they were naturally ordered to virtue. Inasmuch namely as reason is deprived of its order to the true, it is the wound of ignorance; inasmuch as the will is deprived of order to good, it is the wound of malice; inasmuch as the irascible is deprived of its order to the arduous, it is the wound of infirmity; inasmuch as the concupiscible is deprived of its order to the delightable according to reason, it is the wound of concupiscence.

2. On the part of conversion: by actual sin, just as by every human act, an inclination to similar acts is made; which disposition is an obstacle by which man is impeded lest he be easily borne toward the opposite good of virtue. The very inclination to virtue is therefore diminished, not indeed in itself (and accordingly it cannot be totally corrupted), but inasmuch as to it is positively opposed an impediment of attaining the term. Hence by actual sin the four wounds inflicted by original sin are increased and aggravated.

516. Observation. — Hence is understood the doctrine of the Scholastics, according to whom sin as effect has privation of mode, species, and order:

« Mode, species, and order follow every created good, inasmuch as such, and also every being. For every being and good is considered through some form, according to which the species is taken. But the form of each thing... is according to some measure... and from this it has a certain mode, which regards the measure. From its form however each thing is ordered to another. Thus therefore according to the diverse degrees of goods there are diverse degrees of mode, species, and order.

a) There is therefore a certain good pertaining to the very substance of nature, which has its mode, species, and order; and that is neither deprived nor diminished by sin.

b) There is also a certain good of natural inclination, and this also has its mode, species, and order; and this is diminished by sin... but is not totally taken away.

c) There is also a certain good of virtue and grace, which also has its mode, species, and order; and this is totally taken away by mortal sin.

d) There is also a certain good which is the very act ordered, which also has its mode, species, and order; and the privation of this is essentially sin itself (as to the formal element).

And thus it is evident how sin is the privation of mode, species, and order; and it deprives or diminishes the mode, species, and order » q. 85, a. 4.