Temperance is the mean state with regard to physical pleasure, while licentiousness is the vice of excessive yearning for physical pleasure. The grossest pleasures are those of taste, and especially touch, which are most liable to be sources of licentiousness. The licentious person feels not only excessive pleasure with regard to physical sensations, but also excessive pain when deprived of these pleasures. The vice of deficiency toward pleasure is so rare that it lacks a name, though we could perhaps call it insensibility. The temperate person will feel appropriate amounts of pleasure, and only toward those things that are conducive to health and fitness.
The problem of free will is much debated in modern moral philosophy. Presumably, we can be held morally responsible only for those actions that we perform of our own free will, so determining the source and scope of our freedom would seem a necessary prerequisite to determining the source and scope of moral responsibility. Discussing free will raises a number of metaphysical problems, however, foremost of which is the problem of determinism. If we are subject to predictable and unchanging physical laws, then we have no freedom to do what we want. Some philosophers argue that free will is an illusion, some argue that determinism is an illusion, and some argue that a proper understanding of the concepts of free will and determinism will show that the two concepts are in fact compatible.
Aristotle seems strangely unconcerned with the metaphysical vagaries of free will. He makes no mention of the concept of free will, thus avoiding the metaphysical question of whether free will can be compatible with determinism. Furthermore, he seems to avoid any strict definition of responsible action that might delimit for us precisely what kinds of actions we should be held responsible for. At best, he gives us a negative definition, telling us that we are not responsible for actions done under ignorance or compulsion.
However, Aristotle adds some caveats. Ignorance is only an acceptable excuse if we are not responsible for our ignorance. Aristotle seems to agree with Socrates’ claim that no one knowingly does evil and that all wrongdoing is a result of ignorance. He suggests in Chapter 4 of Book III that everyone aims to do good, but bad people, in their ignorance, aim at the apparent good that is in fact not good.
The question, then, is to what extent we can be held responsible for our ignorance. Aristotle’s answer seems to be that the ignorance must be related to particular circumstances over which the agent had no control. For instance, a man is not responsible for poisoning a friend if he had no way of knowing that the drink he gave this friend was poisoned. However, a man who lacks a proper sense of virtue and who does a bad deed through ignorance of what is good is certainly responsible for his badness.
Aristotle similarly explains compulsion. He takes a particularly stern stance on the question of what sorts of compulsion render an act involuntary: involuntary acts are only those that do not originate with the agent. For instance, if someone pushes me into you, I have bumped you involuntarily, because my sudden movement did not originate with me.