Logical nativists contend that human languages and their learners exhibit deep-seated regularities. Many of these regularities, or core linguistic principles, pertain to logical expressions, including both the basic meanings of logical expressions and the interpretations given to combinations of these expressions. Because core linguistic principles are candidates for innate specification, they are expected to meet the diagnostics of innateness. These diagnostics can, in turn, be used to distinguish the logical nativist approach from the experience-based approach. Let us briefly review these features.

First, linguistic phenomena governed by core linguistic principles are expected to be universal. Second, core linguistic principles are expected to range over several phenomena, including ones that may appear on the surface to be unrelated. If abstract principles pertain to clusters of facts that appear to be unrelated on the surface, then these principles provide a unique testing ground to distinguish the logical nativist approach from the experience-based approach, such as the constructivist model discussed in Chapter 2. Because the experience-based approach postulates shallow linguistic representations, it follows that the experience-based approach and logical nativism make radically different empirical predictions about the nature of language, and about the language acquisition process. For one thing, core linguistic principles are expected to be evident in children’s language as soon as they can be tested, even where children lack decisive evidence for them in the primary linguistic data.