We’re still in the introductory phase. So, here’s another “what are we talking about” sort of post, in which I make distinctions rather than arguments.

The words ‘libertarian’, ‘right libertarian’, ‘left libertarian’, ‘classical liberal’, and so on, are used in all sorts of different ways. For the purposes of this blog, I will use the word ‘libertarian’ more or less as Peter Vallentyne does here. His usage seems standard in philosophy, if not outside philosophy

Let’s say libertarians ground their theories of justice on the idea of self-ownership. (They don’t just assume this is true—they usually have arguments for this conclusion. But it’s their starting point for doing political philosophy.) Libertarians left and right agree that people are full self-owners, and in virtue of being full self-owners, have a strong and extensive set of rights over themselves.

Stereotypical libertarians (the ‘right’ libertarians) believe that the world’s resources begin in an unowned state, and to respect people’s self-ownership, people must be allowed to acquire strong property rights in the pieces of the world. Such property rights are regarded as extensions of people’s self-ownership.

In contrast, left libertarians hold either that that the world’s resources are in some way by default commonly owned by all or that the commercial value of those resources is in some way by default commonly owned by all.

Left-libertarians often affirm welfare state-like provisions.  However, they do so not out of a commitment to social justice, but out of a view of what it takes to render private property ownership consistent with the starting point of common world ownership (or common ownership of the economic value of the world’s resources). To put it bluntly, on the left libertarian view, the world (or the value of the world) belongs to everyone. If an individual uses or privatizes a resource, he owes everyone else payment for using their stuff.

‘Liberal’, ‘libertarian’, ‘high liberal’, ‘left libertarian’, ‘right libertarian’, etc, are archetype concepts. We can’t really give necessary and sufficient conditions for them, and the margins between them will be fuzzy.