&gt; What do people who believe this use as their reason for refraining from harming others for personal gain?<p>This is an interesting and deep question! The game theory of life. I don&#x27;t know the answer or if there is a clear answer, but I imagine there&#x27;s generally a lot of risk involved in harming others for personal gain, and basic fear of individual or group retaliation (either mob or police) is a significant deterrent.