Finally Aristotle’s concept of the hexis or habit system—“a settled disposition of character, acquired gradually by persistence in… practice”—was basic to the Hellenistic thinkers. Aristotle stresses “the difficulty of changing one’s disposition once it is developed,” and thus focuses “on development of the young more than conversion of the mature.” The challenge is so formidable because “the beliefs that ground the emotions are bound up with one another” so that the appeal to any emotion will engage the entire disposition, and in order to change a single element of one’s ethical makeup one might have to change the whole arrangement. Solving this problem might be said to be the principal goal of both the Stoic and Epicurean ethical systems.
As Aristotle describes the process there seems to be no discontinuity in it, no fissure where he recommends a strategy of interference. The overwhelming emphasis he places on the hexis, or formed disposition, diminishes the prominence of the element of voluntary choice. It is true that the action must be caused by an orexis, or desire, but this desire is not a free decision. It is produced mechanically by the combination of the external stimulus with the established disposition (hexis) of the individual. At an early stage of personal development, before the hexis is fixed by habituation (e-thos), some deliberate formative influence can be exercised upon it, whether by oneself or by others, such as parents and teachers. “States of character,” says Aristotle, “are formed from similar activities”:
It is by building that people become builders and by playing an instrument that they become musicians … It is by doing just actions that we become just … states come about as a result of similar activities. (NE 1103a44–b25)
Repetition of actions imposed in childhood does most of the hexis-formation. Each individual has voluntarily participated at an early stage in the formation of his hexis, and thus is ultimately responsible for any actions produced through it, however mechanically (see NE 1114a3ff.), but it is not clear that one can interfere in the hexis after it has developed to a certain point. In the Nicomachean Ethics (1114a12–21, 1137a4–9) it seems that “when character has once been established it cannot be changed at will.” Sometimes the point is softened as in a later passage of the same work: “It is hard, if not impossible, to remove by argument (i.e., by philosophy) the traits that have long since been incorporated in the character” (NE 1179b16—17). The psyche– involves “a non-rational element capable of responding to reason,” but also capable of responding to other types of persuasion; if reason gets to it at an early age through a parent or a teacher, well and good; if not, the connections that wire the hexis are made anyway, by other ambient forces, and are likely to remain in place despite subsequent rational persuasion.
In the De Anima (432b26–433a1) Aristotle seems to leave room for interference or voluntary guidance of the process:
Even when the mind does think of an affective object (one which might serve as a trigger for action), it does not at once give orders to avoid or pursue. For instance, it often thinks of something that provokes fear or pleasure, but does not give the command to be afraid though the pulse-rate increases or, if it is a case of pleasure, something else (the penis).
Again, evidently, the fissure or discontinuity where the sequence might turn either way is said to lie between the phase of recognition-with-hedonic-feeling and the phase of emotional-response or impulse-reaction. But for Aristotle the route of intervention does not seem likely to succeed, as the hexis has been bound together by early pleasure-pain conditioning:
Moral virtue is a matter of pleasures and pains; it is for the sake of pleasure that we do what is bad, and because of pain we fail to do what is good. Hence we must be brought up from youth, as Plato, says, to feel pleasure and pain about the right objects; that is right education. (NE 1104118–13)
The point is that the mind commands responses according to its habituated disposition, not with a decision made freely for each specific case. Aristotle does, in a handful of passages, seem to believe in a faculty of choice (prohairesis) which has some autonomy from the hexis, but not much. Fundamentally it is not a free choice in most cases: The mind chooses responses according to its disposition, that is, through a habitual choice; and once the habit, or disposition, is firmly fixed, it seems more or less unchangeable. So no decision is really free or uncaused; all are determined by past events.