In order to be free and prosper, a society must be made up of people who cooperate, voluntarily, with each other, while also pursuing their own personal interests. As a matter of fact, working towards personal gain has positive effects on the entire community.
The simple production of a pencil, for example, involves thousands of people offering their services in exchange for payment. Many of these people will never see the finished product, they will not know exactly what they are working on, they don’t know each other, and they probably speak different languages and practice different religions. Yet their cooperation allows the pencil to be made and subsequently bought; which is why all economic activity needs to be based on this kind of exchange. After all, the father of modern economics, Adam Smith, has always advocated this idea, especially in his book, The Wealth of Nations, published in 1776.
If we look at the bigger picture, it is clear that the economy is not the only system based on cooperation between individuals pursuing their own interests; let us consider language, for example. The origins and subsequent evolution of language are the result of intensive communication between individuals, which was never coerced or planned, and people involved in the conversation benefit from coming to an agreement about which words to use. Scientific knowledge follows the same principle: academics collaborate with each other because they find it mutually beneficial for their respective research. These two cases disprove the belief that self-interest is always materialistic and selfish; in reality, it can also serve other values that go far beyond a person’s bank account.