Chicagoan theories of and policies for unpriced natural resources have gathered momentum over the past twenty years and have reached a fair degree of acceptability among some agricultural economists and some governments. The critical evaluation of the logic, explanatory and predictive power of these theories, which is undertaken in this paper, shows that this acceptability is not well founded. It is demonstrated that these theories embody substantial logical shortcomings and rely on hypotheses which may be falsified. These limitations have important implications for Chicagoan resource policies. Game theory is used to show that Pareto optimality cannot be reached when Chicagoan policies are implemented by a government, contrary to the contention of Chicagoan economists.