William Harvey's De generatione uses a quotation from Seneca's Epistula 58 together with material from Aristotle to oppose the cognitive processes and methods of the artist to those Harvey wishes to require for the anatomist. This paper studies ways in which Harvey, as a deliberate writer, makes rhetorical uses of that opposition to expose false anatomists as those who rely on books rather than on observation and who promulgate sciolist fictions. In showing that they contrast to true anatomists, whose statements (...) derive from careful observation, and to imaginative artists, whose fictions do not claim to be verifiable truth, Harvey achieves a work establishing the status of the science of reproduction and summoning others to the proper method of practising it. (shrink)