Now let us consider the quality of self-governance. If a person has self possession, they have self-governance. Not only are they responsible for their own actions, but they are responsible for the quality of their own actions. It is destructive to the person merely to take responsibility for robbing a bank. While that is a good thing after-the-fact, self-governance means that the person controls his actions. And refuses to rob the bank. To what end? To the end of human flourishing. Self-governance is the quality that directs our free acts to the existential ends that God placed in our nature, so that we can live a truly human life as the imago Dei.
Each of these existential ends has an end or purpose, and can be divided into the least necessary all the way up to the more important. The necessary are those things which make life possible, but can never be desired just for themselves, for the very reason that the are not important to our full flourishing, but are only basic to it. So, food, clothing, shelter and the like are necessary, but the person who desires them for their own sake stunts his development. These make it possible for us to go to higher and higher levels, or from the necessary to the important. So Karol Wojtyla considers the relations between persons, especially from the heart, as the most important feature in developing full humanity. We can say that the persons of the Trinity itself are known by their relations among each other, where each person is completely self-giving to the other two.
Other important existential ends are the desire to know people and things outside of ones own geographic area; the desire to learn, the desire for love and family; the desire to contribute something to society. Lastly is the desire to be on good terms with the Creator.
But these ends cannot be reached unless and until the self-possessed person is self-governing, that is, until he controls and directs his actions to the ends. Every day one is confronted with a myriad of choices. Not all of those choices are moral/immoral or life and death choices. But they are choices which either enhance human flourishing or detract from it. People who live impulsively are not self-governing. They allow their emotions, their mere likes and dislikes, to control what actions they take. Self-governance means that they have control over their passions and desires. They consciously choose the better path; they accept grace and the good because the have a notion about how the existential ends can be accomplished and reject those things which lead away from them.
Take marriage for example. Think of the person who goes to Las Vegas, meets someone, and after one day heads to the Elvis Chapel to get married—heads to the Elvis Chapel to promise a person they just met that they are ready to commit to love this person in sickness and health, for richer or poorer, for better or worse, until the end of life. These are two people who have no self-governance. They have thrown away an opportunity to make a choice to develop their character to accomplish an important existential end. Is it any wonder that the divorce rate is so high. This is an extreme example, but is it not true that many, if not most, people live their lives this way, doing things on impulse, spur-of-the-moment, no thought required?
Now we should ask ourselves what life would be like if the famous people in the past or even the present lived like this. Thomas Edison would have never invented the light bulb, because he might have enjoyed fishing instead. Great authors would have never written their books, because it was too hard, required too much thinking or research. No one would have ever set up a business because the risk was too much to handle. And why should emergency room physicians and paramedics put up with so much blood, gore and suffering in others, when they could be doing something less stressful? All these people do this because they are self-possessed and self-governing. The overcome their aversion to the difficult and their natural desire to pleasure and relaxation to accomplish a good, both for themselves and for the flourishing of society.
Therefore, we can conclude that the less self-possession and self-governance the people in a society have, the more the society will languish, and the more the individuals in that society will fail to reach their full potential.