Abstract
The standard allocative efficiency criteria used by economists (Pareto efficiency and Kaldor-Hicks efficiency) are fundamentally unable to rank a slave-labor system against a free-labor system. Given either set of initial property rights assignments the market can reach (or fail to reach) allocative efficiency (that is, allocate resources to their highest-valued uses), but welfare economics provides no meta-framework for ranking initial assignments. This finding underscores the limits to the usefulness of efficiency criteria: they cannot settle all questions, and unfortunately are least decisive just where the stakes are greatest (namely, where wealth effects of alternative assignments are greatest). Explicitly ethical criteria are needed to make the ranking. Key Words: Pareto efficiency Kaldor-Hicks efficiency property rights welfare economics.