Self-interest is good, altruism is evil.
But before we investigate this issue, keep in mind that clear definitions are critical in evaluating statements about the morality of self-interest and altruism. This is especially critical here because both concepts have more than one definition.
One definition of self-interest, selfishness, or egoism is mindless emotionalism. You should do anything you feel like doing. But doing what you want, if based on mindless emotion devoid of reason and ethics is, harmful. Taking illicit drugs could kill you. Smoking will take many years off your life. Rejecting education makes you unemployable. Committing crime may put you in prison. Spending money mindlessly can leave you bankrupt. Treating your partner cruelly can end your chance for romantic happiness. Lying can destroy all your friendships. Conforming blindly to popular opinion leads to other people controlling your life.
In contrast, rational egoism requires thinking about what is actually good for you, including respecting the rights of others. You need to think, for example, about what is good for you to eat and drink. It is in your self-interest to get educated and to develop work skills that will bring you success in your job and career. Being honest in all your relationships leads to you being trusted. Rejecting crime means staying free to act. Romance includes voluntary and honest economic cooperation and spiritual (conscious) exchange between people—mutual enjoyment of each other “you and me together”. In this way, self-interest is moral. It means that you are acting in accordance with what is actually good for you and you would want others to do the same.
Now consider altruism. The original meaning of altruism is “other-ism.” Under this philosophy, you have no rights, no personal values, and no self. You exist only to serve. You are nothing.
But the term is also used, in contradiction to its original meaning, in another way: to refer to helping and supporting others whom you selfishly love or care about, such as your romantic partner and children. You might give money to your children or grandchildren so that they can attend college. You might donate to charities whose goals you support because you can afford the time and money because you take pleasure in seeing the charity fulfill a mission you personally support. True altruism, in contrast, would be serving others whom you do not like or giving donations you cannot afford or to a cause for which you have no interest. Better yet, it would mean sacrificing as a duty to a person or cause that you despise. Worst of all, it would mean, in the name of morality, marrying someone you do not even like out of pity. To be consistent, the sacrifices would have to go down the line. The person who first received your sacrifice would be selfish to accept it so they would have to give it to someone even more needy and so on until everyone in the world was unhappy down to the last miserable person on earth. No one could live this way.
What about police officers and soldiers who risk their lives every day to protect our rights? Are they altruists? The key to answering this question is to ask another question: Do they personally love this work? Does it have personal meaning? Not everyone wants to be a police officer or soldier, but for some people, that is a personally important job. These people enjoy and love protecting their city or country. They are proud of their role and admire the values their city or country stands for. They are, in fact, acting in their own self-interest if helping others involves a personal value (i.e., freedom).
Rational self-interest is good, including when used to help others whom you value, but true altruism (as opposed to helping valued others) works against human life and happiness. (For a deeper look at the virtue of self-interest, see Objectivism The Philosophy of Ayn Rand by Leoanrd Peikoff, 1991).