As a radical individuals I don’t subscribe to the idea of objective morality. If such a thing as objective morality existed, the human race would have had no choice by to agree with each on the matter. But if you ask 10 individuals to describe their beliefs of what is moral and what is immoral, you’ll likely hear 10 different systems of morality.
When I express my disbelief in objective morality, especially to libertarians, I’m usually met with a lengthy explanation of how a world without objective morality would devolved into a world of murder, rape, and pillage. It’s the same argument Christians often make against atheists. Without a belief in God, they believe people will just murder, rape, and pillage. However, people who make these arguments make two mistakes. First, they assume that all morality must be established by an outside force. Second, they believe morality and consequences are interchangeable.
My disbelief in objective morality doesn’t mean I don’t have a system of morals. As I noted above, if you ask 10 individuals to describe their moral beliefs, you’re likely to get 10 different answers. Each of those individuals will express a system of morality to you, indicating that they do have an established system of morality, but disagree on the definitions of moral and immoral. They will disagree on the definitions precisely because they have established their own system. While their system may be heavily influenced by outside forces, such as philosophy, it is a system unique to them. I, for example, have a self-defined system of morality. While I think that it’s a pretty good system and the world would be a better place if everybody lived by it, I have no way to prove objectively that it is a good system and the world would be a better place if everybody lived by it.
The second failure objective moralists often fall into is treating morality and consequences as interchangeable concepts. While an absence of a moral system may give an individual the excuse to murder, rape, and pillage, they very well might avoid performing those actions because they realize doing so could lead to severe consequences. If you try to murder or rape somebody, they might kill you in self-defense. If you try to pillage a neighborhood, the people living there might kill you in self-defense. Even if you managed to get away with such actions, somebody is likely to search for you or hire somebody to search for you so that their idea of justice can be exacted. Even sociopaths tend to understand that actions have consequences and that can often regulate their behavior.
Socialists and libertarians strongly disagree on what constitutes morality. Even though they disagree on morality they can often live together in relative peace. Why? Because they both recognize that their actions have consequences. If a socialist tries to appropriate a libertarian’s means of production, the libertarian might use violence to dissuade the socialist. Likewise, if a libertarian decides that a group of socialists is a threat to their private property and attempts to use violence against them, the socialists may respond with violence of their own.
Just because somebody doesn’t believe in objective morality, or morality of any kind, doesn’t mean they’re going to murder, rape, and pillage.