Information theoretic semantics proposes to construe predicate reference in terms of nomological relations between distal properties and properties of representational mental events. Research on the model has largely concentrated on the problem of choosing the nomological relation in terms of which distal properties are to be singled out. I argue that, in addition to this, an information theoretic account has to provide a specification of which properties of representational mental events will play a role in determining reference,qua bearers of nomological relations. I contend that this task poses a serious additional challenge to the viability of the model.