Reply Obj. 3: It is impossible for anyone to have an actual knowledge or true opinion about a universal affirmative proposition, and at the same time a false opinion about a particular negative proposition, or vice versa: but it may well happen that a man has true habitual knowledge about a universal affirmative proposition, and actually a false opinion about a particular negative: because an act is directly opposed, not to a habit, but to an act.

Reply Obj. 4: He that has knowledge in a universal, is hindered, on account of a passion, from reasoning about that universal, so as to draw the conclusion: but he reasons about another universal proposition suggested by the inclination of the passion, and draws his conclusion accordingly. Hence the Philosopher says (Ethic. vii, 3) that the syllogism of an incontinent man has four propositions, two particular and two universal, of which one is of the son, e.g. No fornication is lawful, and the other, of passion, e.g. Pleasure is to be pursued. Hence passion fetters the reason, and hinders it from arguing and concluding under the first proposition; so that while the passion lasts, the reason argues and concludes under the second.

Reply Obj. 5: Even as a drunken man sometimes gives utterance to words of deep signification, of which, however, he is incompetent to judge, his drunkenness hindering him; so that a man who is in a state of passion, may indeed say in words that he ought not to do so and so, yet his inner thought is that he must do it, as stated in Ethic. vii, 3. ________________________

THIRD ARTICLE [I-II, Q. 77, Art. 3]

Whether a Sin Committed Through Passion, Should Be Called a Sin of
Weakness?

Objection 1: It would seem that a sin committed through passion should not be called a sin of weakness. For a passion is a vehement movement of the sensitive appetite, as stated above (A. 1). Now vehemence of movements is evidence of strength rather than of weakness. Therefore a sin committed through passion, should not be called a sin of weakness.

Obj. 2: Further, weakness in man regards that which is most fragile in him. Now this is the flesh; whence it is written (Ps. 77:39): "He remembered that they are flesh." Therefore sins of weakness should be those which result from bodily defects, rather than those which are due to a passion.

Obj. 3: Further, man does not seem to be weak in respect of things which are subject to his will. Now it is subject to man's will, whether he do or do not the things to which his passions incline him, according to Gen. 4:7: "Thy appetite shall be under thee [*Vulg.: 'The lust thereof shall be under thee.'], and thou shalt have dominion over it." Therefore sin committed through passion is not a sin of weakness.

On the contrary, Cicero (De Quaest. Tusc. iv) calls the passions diseases of the soul. Now weakness is another name for disease. Therefore a sin that arises from passion should be called a sin of weakness.

I answer that, The cause of sin is on the part of the soul, in which, chiefly, sin resides. Now weakness may be applied to the soul by way of likeness to weakness of the body. Accordingly, man's body is said to be weak, when it is disabled or hindered in the execution of its proper action, through some disorder of the body's parts, so that the humors and members of the human body cease to be subject to its governing and motive power. Hence a member is said to be weak, when it cannot do the work of a healthy member, the eye, for instance, when it cannot see clearly, as the Philosopher states (De Hist. Animal. x, 1). Therefore weakness of the soul is when the soul is hindered from fulfilling its proper action on account of a disorder in its parts. Now as the parts of the body are said to be out of order, when they fail to comply with the order of nature, so too the parts of the soul are said to be inordinate, when they are not subject to the order of reason, for the reason is the ruling power of the soul's parts. Accordingly, when the concupiscible or irascible power is affected by any passion contrary to the order of reason, the result being that an impediment arises in the aforesaid manner to the due action of man, it is said to be a sin of weakness. Hence the Philosopher (Ethic. vii, 8) compares the incontinent man to an epileptic, whose limbs move in a manner contrary to his intention.