The general justification: No man should be ruled by another man. Individual sovereignty, moral autonomy, dignity, soul, whatever you wish to call it, demands that a person refuse to be ruled. What about the "capitalist" part? There are several justifications given by various anarcho-capitalists.
- The life of man qua man, man as a rational being, morally necessitates a laissez-faire economic system (Ayn Rand and objectivists).
- Man must be free and uncoerced so that the man, especially his moral faculty, is allowed to evolve. (Herbert Spencer).
- There is an overriding moral principle in civilised society: that no one should violate the (general moral) rights of others, i.e. initiate force or threat of force. This is called the NAP - Non-Aggression Principle (Spencer, Rand, Rothbard).
- Capitalism is contractual; it is what rational people implicitly agree to do when they enter society (Narveson).
- Libertarianism capitalism is simply what society will do more or less in many or most places in the absence of a State (David Friedman). This is a a utilitarian or "value-free" economic approach.
- One cannot argue against anarcho-capitalism without implicitly agreeing to its basic assumptions (Hans-Hermann Hoppe's argumention ethic).