Moreover, he identifies specific virtues or excellencies that a good man should acquire. He notes that these virtues reflect that right balance between intellect and desire, reason and emotion, or head and heart. Right reasoning must be accompanied by right desires.
So how do we actually acquire these virtues?
Aristotle gives a strange answer, one that is counter-intuitive to most people.
Using the example of the virtue of courage, Aristotle writes that the path to become a courageous person starts with performing courageous acts.
Wouldn't someone have to possess courage already to perform a courageous act? Wouldn't someone already have the ability to act bravely under a sudden attack or persevere and overcome the fears that often accompany disease or poverty or some other challenge?
To a point, yes. Aristotle, however, conceives of virtues not as a one time or occasional manifestation. He sees them as parts of a person's permanent character. And that comes through habituation. When one performs that first act of courage, that makes is easier to perform a second, and a third, etc. Soon courage will become an ingrained habit.
The same goes for other virtues as well.
For example, everyone knows people who seem to always be there for others in a time of need. Sometimes we say they have the gift of compassion, as if they came into the world that way. Not really; they have the habit of compassion. They responded to some one's need that first opportunity and then repeated that response again and again. Soon it became a habit. Now they do not even think about it anymore.
Again, everyone knows people who respond to crises with fits of rage. They curse, they throw things, and they hit things (or people). How did they get that way? They made it their habit. They may at one time have reacted in frustrations in all kinds of ways. Through repeated fits of rage, however, they eventually made that their habit. And now people who know them, when a crisis arrives, come to expect a display of a fit of rage.
From the perspective of the big picture, it gets back to the question of human nature.
Everyone has an opinion about what is exactly human nature. Some people, especially liberals, seem humans as essentially good. Others, like Christian fundamentalists, refer to human nature as “sin nature.” Many anthropologists, aware of the endless diversity of customs around the world, deny that humans have a nature at all.
If someone asked Aristotle, he might answer that human nature is potentiality. And we actualize our potentiality through the choices we make by our reason and will. Unlike animals driven by instinct, humans must use reason to reflect upon what kind of persons they will be. In that sense, we are the only creatures that make ourselves.
So through our choices and repeated actions, we create habits good and bad. Many actions or habits become so ingrained that we do not even think about them. They become second nature.
So when our reasoning is right and the desires are right, human virtues or excellencies become part of our character through habituation. When they do, Aristotle evaluates that person as morally virtuous.
Likewise, when the reasoning or desires are wrong, human vices likewise become part of our character through habituation. Aristotle calls people dominated by these vices the morally vicious.