Economic theory tells us a lot about the nature of political actors along with the inadequacy of their knowledge in regulating society to bring about the common good. All rational men act purposefully to remove uneasiness from their lives. They try to maximize those things in life that give them the greatest satisfaction (e.g., money, love, power, influence, charity, altruism, holiness, etc.). However, they also act in such a way that engenders cooperation with others, facilitating and exploiting mutually beneficial gains from trade. Peaceful cooperation is the result of the operation of the market economy. People pursuing their own self-interest voluntarily cooperate to provide the needs and wants demanded in society.
We must be careful to not equate self-interested motives with selfish ones. The former describes one’s economic motivation while the latter deals with one’s character. For example, a person might have altruism or to “shepherd the flock of God” (1 Peter 5:2) as his highest goal. He would thus pursue the self-interested agenda that he believes has the highest probability of attaining that goal. He might also pursue other things along with this objective, such as owning his home debt-free, raising four children, and taking his wife on an annual skiing trip. But all these elements (and others we might think of) mix together into concerted, purposeful, self-interested action to attain the conglomerate goal.