So far I have discussed two barriers to happiness. One is a lack of stability. The second is error. The final one is irrationality. Irrationality makes us unhappy.
Irrationality appears in many ways. There are a number of ways to be rational, but combining any of them with irrational actions, reasons or motives means that the action is irrational. So it is better to speak of what makes an action rational rather than what makes it irrational. Acting against any way to be rational is irrational.
The first way to be rational is to pursue happiness. To act so that we are happy is what is most important. There is a simple argument for this. Every action is done in order to fulfill some desire. If one did not desire something in any respect, then one would not do the action. Every desire is done in order to pursue what the person believes is good. So every action is done to pursue what the person believes is good. That is the ultimate purpose behind the action. What is most important is what is best for us. So pursuing our own good is what is most important for us to do. Pursuing our own good is what makes us happy. Therefore, pursuing our own happiness is what is most important for us.
The second way to be rational is to pursue the best means to achieve our own happiness. Since happiness is our highest goal, the best means should be sought for it. This is self-evident. However, this does not mean several things. First, it is by no means obvious that immoral actions will make us happy over the long term. If they do not, then it would be counterproductive to use immoral actions to advance our own happiness. Second, there is no reason to assume that our own happiness must crowd out actions that help others even at our own expense. We don’ t know that because we might be happy because others are happy. Our happiness might also require some actions to help others. Third, there is no reason to believe that pursuing our own happiness might be safe. It might be dangerous. Without knowing what it is that makes us happy, there is no way to know whether it is safe or dangerous.
The third way to be rational is to act with rationality with respect to what we know. This means that we should accept what we know to be true, be honest, and always follow where logic leads us. The reason for this is simple. In order to pursue the best means for happiness we must know what those means are. If we deceive ourselves about happiness, then it is quite possible that we will not ever achieve it.
As long as we are rational, avoid mistakes and ground our happiness in something circumstances cannot disrupt then we will achieve happiness and not lose it. The problem is that doing those things requires understanding what came before. We need to know what desire and belief are and how happiness is related to them. Once we know these things, then we can determine what will make us happy and how to maintain that happiness.