论人的行为（第一部分）

Reply Obj. 1: The involuntary is opposed to the voluntary. Now it has been said (A. 4) that not only the act, which proceeds immediately from the will, is called voluntary, but also the act commanded by the will. Consequently, as to the act which proceeds immediately from the will, violence cannot be done to the will, as stated above (A. 4): wherefore violence cannot make that act involuntary. But as to the commanded act, the will can suffer violence: and consequently in this respect violence causes involuntariness. Reply Obj. 2: As that is said to be natural, which is according to the inclination of nature; so that is said to be voluntary, which is according to the inclination of the will. Now a thing is said to be natural in two ways. First, because it is from nature as from an active principle: thus it is natural for fire to produce heat. Secondly, according to a passive principle; because, to wit, there is in nature an inclination to receive an action from an extrinsic principle: thus the movement of the heavens is said to be natural, by reason of the natural aptitude in a heavenly body to receive such movement; although the cause of that movement is a voluntary agent. 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. Consequently this cannot be called involuntary.