 Non-reductive physicalism of this sort denies that the theoretical and conceptual resources appropriate and adequate for dealing with facts at the level of the underlying substrate or realization level must be adequate as well for dealing with those at the realized level (Putnam 1975, Boyd 1980). As noted above in response to the How question, one can believe that all economic facts are physically realized without thinking that the resources of the physical sciences provide all the cognitive and conceptual tools we need for doing economics (Fodor 1974).