Abstract This paper explores the ambiguity of the “human machine”. It suggests that anthropomorphism results from a “default schema” applied to phenomena, including machines, that a perceiver finds otherwise inexplicable. Mechanomorphism, the attribution of machine characteristics to humans, is a culturally derived metaphor that presently dominates cognitive science. The relationships between anthropomorphism and mechanomorphism pose a special difficulty for the question, “Can machines think?” Does a positive response reflect a cognitive bias on the part of the perceiver or a genuine attribute of the computer? The problem is illustrated for Turing's “imitation game” for thinking machines, and a strategy for constraining anthropomorphic attributions is proposed.