I start with Aristotle’s theory of definition in order to claim that Aristotle could not reasonably have included the catharsis clause in the definition of tragedy on his own strictures. Moreover, in case we could solve this problem, I expose some very serious shortcomings that result in the Poetics itself, which are never or rarely acknowledged, if the catharsis clause is kept. Finally, given statements of Strabo and Plutarch, I suggest that the clause was probably a mistaken interpolation by an editor who repaired a damaged Aristotelian manuscript or who imagined that he was augmenting deficient Aristotelian doctrine. M.D. Petrusevski ingeniously thought that the original manuscript contained the words pramatön sustasin, “structure of actions,” that the words were corrupted, and unfortunately restored as we have them, pathématân katharsin.15 However, I shall argue ultimately that the whole catharsis clause, whether or not intended as a repair, is an illegitimate addition and should be marked accordingly.
Scott, Gregory, "Athetizing the Catharsis Clause in the Poetics" (1997). The Society for Ancient Greek Philosophy Newsletter. 249.