Quote Originally Posted by Kralizec View Post
Legal positivism was aimed at creating predictable rights and obligations by creating a transparant, clear system of laws. Theoretically, judges would only rely on statutes and such instead of local customs, "natural law" or subjective notions of morality. They rejected the idea of "natural law" specifically because law & justice are man-made concepts. I have absolutetly no idea where you got the idea from that legal positivism is about exhaustively summing up the things a person is allowed to do, and forbid him from doing anything not expressly allowed; it simply isn't true.
In the UK you can do something unless they pass a law against it, in a positivistic legal system if the government ries to stop you doing something you have to prove a legal right to be able to do it. In practice it does work like that, just like the US government has to justify its rights of government (the opposite principle).

Also, positivism assumes that Rights are not inalienable, worse (as you have already noted) it decouples Justice and Law. Justice is not "man-made" any more than "happiness", Justice is a metaphysical concept. A legal system without metaphysical undergurding is just due process.