Libertarianism is a system for resolving conflict. In other words, it is an ethical system. Libertarianism simply tells you not to commit crimes like theft and murder. So, it only applies to how you interact with other people, and even then only sets some bare minimum of acceptable behavior.
This invariably leads people to ridicule libertarianism because it does not give any guidance on activities that are not crimes. Should you donate to charity? Libertarianism doesn’t say. People who don’t like libertarianism phrase this as, “libertarianism does not support charity, ” which is technically true but very misleading. Many libertarians give to charity, but they do not do it because they are libertarian. They have other codes of behavior that motivate them.
These other codes are called moral systems. They help people decide what is good and what is bad. For example, Jainism says that drinking alcohol is bad. Like libertarianism, a moral code might dictate how to interact with others. On the other hand, moral codes can also deal with how to behave when you are all alone. Some moral codes are compatible with libertarianism and some are not. So even though libertarianism does not tell you what is good and bad, if your moral system says that it is good to murder, then you cannot also be a libertarian.
Some people think that libertarianism is a political theory, and so it relates only to how government should function. Yet, libertarianism can apply to any society, even ones without government. So it is important not to confuse the political efforts of libertarians for the fundamentals of libertarianism. There are certainly libertarian political theories, but they are derived from the libertarian ethical system. Libertarianism is not defined by its political conclusions.
As mentioned, libertarianism is a system for evaluating conflict. When people have a conflict, libertarianism says that the person in the wrong is whoever caused the conflict to happen. That’s why libertarianism can be defined by a single rule for human interaction: do not cause conflict. Though it is a simple idea, it has enormous implications: no war, no taxes, and no limits on lives of peaceful people.
Powerful though it is, libertarianism is not the end of the journey for those who are looking for personal codes of conduct. Everyone needs to decide for themselves if they value family, wealth, technology, art, and all the other things that can be a part of life. Anarcho-capitalism offers a good set of values to adopt and is not only compatible with libertarianism, but actually incorporates it. Yet, even ancaps still have many choices to make before arriving at a fully fleshed-out personal philosophy.
The stakes get even higher when discussing codes of conduct for entire societies. One thief can ruin a family. Government orchestrated theft can ruin a nation. One murderer can devastate a town. Government orchestrated murder can devastate an entire continent. All the more reason to continue to educate people on what libertarianism is, and why it is a wonderful ethical system to bring into your life.