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