"Second, there is the logical gap between “is-” and “ought-statements” which natural rights proponents have failed to bridge successfully—except for advancing some general critical remarks regarding the ultimate validity of the fact-value dichotomy. Here the praxeological proof of libertarianism has the advantage of offering a completely value-free justification of private property. It remains entirely in the realm of is-statements and never tries to derive an “ought” from an “is.”
The structure of the argument is this:
- (a) justification is propositional justification—a priori true is-statement;
- (b) argumentation presupposes property in one’s body and the homesteading principle—a priori true is-statement; and
- (c) then, no deviation from this ethic can be argumentatively justified—a priori true is-statement.
The proof also offers a key to an understanding of the nature of the fact-value dichotomy: Ought-statements cannot be derived from is-statements. They belong to different logical realms. It is also clear, however, that one cannot even state that there are facts and values if no propositional exchanges exist, and that this practice of propositional exchanges in turn presupposes the acceptance of the private property ethic as valid. In other words, cognition and truth-seeking as such have a normative foundation, and the normative foundation on which cognition and truth rest is the recognition of private property rights.”
— Hans-Hermann Hoppe, Economics and Ethics of Private Property