Thomas Aquinas

“ But if a man were to believe the command of the proconsul to be the command of the emperor, in scorning the command of the proconsul he would scorn the command of the emperor. In like manner if a man were to know that human reason was dictating something contrary to God's commandment, he would not be bound to abide by reason: but then reason would not be entirely erroneous. But when erring reason proposes something as being commanded by God, then to scorn the dictate of reason is to scorn the commandment of God. ”

“ Now the good of the whole universe is that which is apprehended by God, Who is the Maker and Governor of all things: hence whatever He wills, He wills it under the aspect of the common good; this is His own Goodness, which is the good of the whole universe. On the other hand, the apprehension of a creature, according to its nature, is of some particular good, proportionate to that nature. ”

“ Now a thing may be considered in various ways by the reason, so as to appear good from one point of view, and not good from another point of view. And therefore if a man's will wills a thing to be, according as it appears to be good, his will is good: and the will of another man, who wills that thing not to be, according as it appears evil, is also good. Thus a judge has a good will, in willing a thief to be put to death, because this is just: while the will of another---e.g. the thief's wife or son, who wishes him not to be put to death, inasmuch as killing is a natural evil, is also good. ”

“ The eternal law cannot err, but human reason can. Consequently the will that abides by human reason, is not always right, nor is it always in accord with the eternal law.
Reply to Objection 3: Just as in syllogistic arguments, granted one absurdity, others must needs follow; so in moral matters, given one absurdity, others must follow too. Thus suppose a man to seek vainglory, he will sin, whether he does his duty for vainglory or whether he omit to do it. Nor is he in a dilemma about the matter: because he can put aside his evil intention. ”

“ Consequently if it be proposed by the reason as something evil, the will tends to it as to something evil: not as if it were evil in itself, but because it is evil accidentally, through the apprehension of the reason. Hence the Philosopher says (Ethic. vii, 9) that "properly speaking the incontinent man is one who does not follow right reason; but accidentally, he is also one who does not follow false reason." We must therefore conclude that, absolutely speaking, every will at variance with reason, whether right or erring, is always evil. ”

“ But if the error arise from ignorance of some circumstance, and without any negligence, so that it cause the act to be involuntary, then that error of reason or conscience excuses the will, that abides by that erring reason, from being evil. For instance, if erring reason tell a man that he should go to another man's wife, the will that abides by that erring reason is evil ”

“ Consequently in order that the thing to which the will tends be called evil, it suffices, either that it be evil in itself, or that it be apprehended as evil. But in order for it to be good, it must be good in both ways. ”

“ The act of the will cannot be said to be good, if an evil intention is the cause of willing. For when a man wills to give an alms for the sake of vainglory, he wills that which is good in itself, under a species of evil ”

“ Hence it is customary to say that a man's will, in this respect, is conformed to the Divine will, because it wills what God wishes him to will.
There is yet another kind of conformity in respect of the formal cause, consisting in man's willing something from charity, as God wills it. ”

“ To the second, it must be replied that the species and form of an act are taken from the object considered formally, rather than from the object considered materially.
To the third, it must be said that there is no opposition of wills when several people desire different things, but not under the same aspect: but there is opposition of wills, when under one and the same aspect, one man wills a thing which another wills not. ”

“ And yet considered materially, while the intention is intense, the interior or exterior act may be not so intense, materially speaking: for instance, when a man does not will with as much intensity to take medicine as he wills to regain health. ”