Abstract
Spelke's book defends two hypotheses about human cognition. First, humans and other species are endowed with core knowledge systems—innate computational structures that use abstract concepts to represent various aspects of the environment. Second, humans, and only humans, acquire natural languages, whose syntax and compositional semantics allow them to construct new concepts by combining the outputs of core systems. We endorse the first hypothesis but doubt that language acquisition alone explains the productivity of human cognition. In particular, we argue against the claim that infants use aspects of language to develop a new conception of other people.