Thomas Aquinas

“ Yet again it must be observed that a principle of movement may happen to be first in a genus, but not first simply: thus in the genus of things subject to alteration, the first principle of alteration is a heavenly body, which is nevertheless, is not the first mover simply, but is moved locally by a higher mover. And so the intrinsic principle of the voluntary act, i.e. the cognitive and appetitive power, is the first principle in the genus of appetitive movement, although it is moved by an extrinsic principle according to other species of movement. ”

“ For the conditions of a voluntary act are satisfied, if it be done on account of something else voluntary: since the voluntary is not only what we wish, for its own sake, as an end, but also what we wish for the sake of something else, as an end. It is clear therefore that in what is done from compulsion, the will does nothing inwardly; whereas in what is done through fear, the will does something. ”

“ Now what is compelled or violent is from an exterior principle. Consequently it is contrary to the nature of the will's own act, that it should be subject to compulsion and violence: just as it is also contrary to the nature of a natural inclination or movement. For a stone may have an upward movement from violence, but that this violent movement be from its natural inclination is impossible. In like manner a man may be dragged by force: but it is contrary to the very notion of violence, that he be dragged of his own will. ”

“ God moves man to act, not only by proposing the appetible to the senses, or by effecting a change in his body, but also by moving the will itself; because every movement either of the will or of nature, proceeds from God as the First Mover. ”

“ Voluntariness requires an act of knowledge in the same way as it requires an act of will; namely, in order that it be in one's power to consider, to wish and to act. And then, just as not to wish, and not to act, when it is time to wish and to act, is voluntary, so is it voluntary not to consider.
Art. 4 - Whether violence can be done to the will? Objection 1: It would seem that violence can be done to the will. For everything can be compelled by that which is more powerful. But there is something, namely, God, that is more powerful than the human will. ”

“ Nevertheless it causes involuntariness in a certain respect, inasmuch as it precedes the movement of the will towards the act, which movement would not be, if there were knowledge. Ignorance is "antecedent" to the act of the will, when it is not voluntary, and yet is the cause of man's willing what he would not will otherwise. Thus a man may be ignorant of some circumstance of his act, which he was not bound to know, the result being that he does that which he would not do, if he knew of that circumstance ”

“ In like manner an act is said to be voluntary in two ways. First, in regard to action, for instance, when one wishes to be passive to another. Hence when action is brought to bear on something, by an extrinsic agent, as long as the will to suffer that action remains in the passive subject, there is not violence simply: for although the patient does nothing by way of action, he does something by being willing to suffer. ”

“ And hence it is that what is done out of fear is essentially voluntary, because its principle is within. But if we consider what is done through fear, as outside this particular case, and inasmuch as it is repugnant to the will, this is merely a consideration of the mind. And consequently what is done through fear is involuntary, considered in that respect, that is to say, outside the actual circumstances of the case. ”

“ Fear regards evil, but concupiscence regards good. Now evil of itself is counter to the will, whereas good harmonizes with the will. Therefore fear has a greater tendency than concupiscence to cause involuntariness.
Reply to Objection 2: He who acts from fear retains the repugnance of the will to that which he does, considered in itself. But he that acts from concupiscence, e.g. an incontinent man, does not retain his former will whereby he repudiated the object of his concupiscence ”

“ New movements in animals are indeed preceded by a motion from without; and this in two respects. First, in so far as by means of an extrinsic motion an animal's senses are confronted with something sensible, which, on being apprehended, moves the appetite. Thus a lion, on seeing a stag in movement and coming towards him, begins to be moved towards the stag. ”

“ But sometimes that which is done through ignorance does not deserve pardon, according to 1 Cor. 14:38: "If any man know not, he shall not be known." Therefore ignorance does not cause involuntariness. ”

“ Further, knowledge is necessary for voluntariness. But concupiscence impairs knowledge; for the Philosopher says (Ethic. vi, 5) that "delight," or the lust of pleasure, "destroys the judgment of prudence." ”

“ Now of human acts some are proper to man; others are common to man and animals. And since Happiness is man's proper good, those acts which are proper to man have a closer connection with Happiness than have those which are common to man and the other animals. ”

“ Otherwise every alteration and generation of simply bodies would be unnatural and violent: whereas they are natural by reason of the natural interior aptitude of the matter or subject to such a disposition. ”