Barsalou's hypothesis that mental representations are constructed by selecting parts of percepts encounters the same difficulties as other empiricist theories: They cannot explain concepts for which instances do not share perceptible features (e.g., furniture) or for which there are no relevant percepts (e.g., the end of time). Barsalou's attempt to reduce falsity to failed pattern matching is an elementary error, and the generativity of his simulators cannot be attained without nonterminal symbols. There is not now, and there never was, any reason to be interested in empiricist theories of knowledge. Abstraction is a fundamental aspect of human cognition.