In the eighth chapter of De Sophisticis Elenchis, Aristotle introduces a mode of sophistical refutation that constitutes an addition to the taxonomy of the earlier chapters of the treatise. The new mode is pseudo-scientific refutation, or “the [syllogism or refutation] which though real, [merely] appears appropriate to the subject matter”. Against the grain of its most commonly accepted reading, I argue that Aristotle is not concerned in SE 8 to establish that both the apparent refutations of SE 4–7 and pseudo-scientific (...) refutations issue in false conclusions. His concern rather is to provide a causal analysis of both classes of apparent refutation alike which will explain why both kinds of apparent refutation are sophistical – and whose solutions are therefore the task of no special science but of a dialectical σλλογιστιϰή τέχνη. I conclude my analysis with the observation that Aristotle exploits the results of SE 8 to fend off inSE 9, 10, and 11 respectively a triad of threats to the very existence of a τέχνη of the resolution of sophistical refutation. The three threats are: the impossibility of omniscience; the relativity of semantic beliefs; and the incapacity of a questioner ignorant of a science to expose the ignorance of a pretender to scientific expertise. (shrink)