From my response to Palmer at Cato Unbound:

Palmer says that no matter what happens to a man on a desert island, the man is neither free nor unfree, because liberty is an inherently social concept. Palmer might want to limit his talk of ‘liberty’ this way. Ordinary people do not, and they are not obviously mistaken in having a range of concerns that are not so limited. Stipulating that they are mistaken will not do.

Before ever reading any philosophy, I would have found it obvious that if Robinson Crusoe were pinned under a log, he would thereby be unfree, and would want to be liberated from the burden of being thus pinned. I likewise would have considered it obvious that when a log pins Crusoe down, this is morally different than when a mugger pins him down, or when a policeman pins him down after Crusoe has robbed a bank. Some philosophers say that because these three cases are morally different, we shouldn’t use the same word. But the question of whether to use the same word is a question about how to be clear. In using the same word, we can obscure differences while emphasizing similarities. Using different terms can obscure similarities while emphasizing differences.

We can just as easily say that in all three cases, Crusoe becomes less free (in the same sense of ’free’), but that the moral significance of these cases is different. In the first case, the situation is regrettable, but no one has done anything wrong. In the second case, the mugging is wrong, not merely regrettable. In the third case, the policeman limits Crusoe’s freedom, but with justification.

Palmer asserts ‘liberty’ can only refer to a certain kind of relationship among people. He thinks other uses of the term are confused…Palmer does not show us why we must confine our use of the term ‘liberty’ to social situations. Like the average English-speaker, I feel comfortable saying that birds are free to fly in a way people are not. If somebody objects that the bird’s freedom to fly is different from the freedom in question when we discuss free speech, I agree. So, ordinary English uses of the term ‘liberty’ refer to many different things, and we philosophers should be more precise by saying what particular kind of freedom or liberty we have in mind.

It's important to remember that Palmer is recommending that we revise our language and restrict our use of 'liberty' to just one of its many commonsense meanings. So, he needs to give us compelling grounds to do so.  

Actually, I'm not even sure why Palmer would assert that liberty is an inherently social concept. It doesn't seem to follow from his view. As far as I can tell, though I might be wrong, he thinks liberty is the absence of wrongful interference. But a person alone on a desert island has as much liberty so defined as she could ever want. After all, no one interferes with her, wrongfully or not. We might even imagine a persecuted person fleeing to a desert island in order to be free of persecution. Palmer could revise his definition of negative liberty and say that negative liberty is the absence, in a social setting, of wrongful interference. But then we need a compelling argument for this definition. An alternative move, which I favor, is to say that one form of liberty is the absence of wrongful interference, and that this form of liberty tends to have a lot of value for us in social settings. It probably doesn't normally have much value for us in desert island situations.