 A few further properties of Lewis’s definitions of theoretical terms are noteworthy. First, they specify the interpretation of theoretical terms uniquely. This property is obvious for the case of unique realization of TC but holds as well for the other cases since assignment of no denotation counts as interpretation of a descriptive symbol in free logic. Second, it can be shown that these definitions do not allow for the derivation of any \(L(V_o)\) sentences except logical truths, just as the original Carnap sentence did. Lewis, therefore, in fact succeeds in defining theoretical terms. He does so without attempting to divide the axioms \(A(\TC)\) into definitions and synthetic claims about the spatiotemporal world.