[geye1234]

How far would you take this? Let's grant that the difference between murder and a just killing is what someone (maybe the guy in power) says it is, nothing more. Would you say the same about robbery? Is it only robbery to point a gun at someone and take his money if someone says it is? If yes, at what point does the distinction between one thing and another thing become real, and not just based on what some guy says?

[neaden]

Well yes, there are times where it legal to take someones possessions/money such as if they owe a debt or have a legal judgement against them. In that case it could mean for instance sheriff deputies showing up at your house with guns and taking things in a manner that would be legal and not be considered robbery. When it becomes one thing or another is going to depend on your position on other things, there is a legal answer for when it becomes robbery/murder but also moral answers. I am for example a moral realist, so my answer to that would be different than someone who was a moral relativist.