 The ontology of natural language is reflected not only in presuppositions, but also in certain kinds of linguistic data that are generally inaccessible to linguistically uninformed philosophical or naive reflection. These are syntactic analyses of sentences that would be unavailable to non-linguists and involve particular ontological commitments. One example is syntactic analyses that posit silent syntactic elements with ontological content. Thus, Kayne (2005: chap. 8) argues that the sentence John has few books contains a silent (antecedent-less) occurrence of the noun number, which suggests that the actual structure of the sentence, John has few number books, involves reference to a number. Another example is syntactic analyses that make use of lexical decomposition with ontological relevance. Thus, Harves &amp; Kayne (2012) argue that the underlying form of the English verb need is have need, which involves an ontological commitment to things like needs that is not evident from the simple verb need alone. Underlying syntactic structures of this sort are posited in generative linguistics on the background assumption that knowledge of grammar is implicit and to an extent innate. If ontological notions go along with such structures, then they should be just as much part of implicit knowledge as the syntactic structures themselves, which means that they will be unavailable to rejection or revision through reasoning.