雖然批評家如沃克（Jeffrey Walker）及柯爾（Thomas Cole）等人，已就亞里斯多德（Aristotle）的思想推敲修辭（rhetoric）與詩學（poetics）之間呼應之處，對其悲劇論的討論，卻未曾留意到修辭說服（persuasion）與悲劇淨化（catharsis）的互聯性。因此，本文旨在申論，淨化的概念與亞氏藉由辯證（dialectic）理解修辭的思考路徑，原為一致。即便此概念涉及情意相關的外延，在根本上仍為一邏輯體：理想上，劇作家須能在理性的庇護下，勾起並排除悲憫及恐懼的情緒。當中，特別需要注意的是在此淨化效應下修辭推論（enthymeme，即不完整的三段式論證法）的角色。亞式企圖莊嚴化文藝創作的嘗試因而極為明顯。準之，本文將先論及在希臘修辭傳統裡詩學的狀況，再闡明亞氏悲劇論的邏輯面向，並明確探討淨化作用所蘊含的修辭推論運作。這樣的修辭取徑可在一具歷史縱深的框架中，脈絡化亞式的淨化說，以及增補傳統上對淨化較為難以捉摸的種種詮釋。

Although critics such as Jeffery Walker and Thomas Cole have elaborated on the correspondence between rhetoric and poetics by way of Aristotle, studies devoted to the Aristotelian tragedy have been inattentive to the interrelatedness between rhetorical persuasion and tragic catharsis. Therefore, this paper purposes to argue that catharsis is a concept integral to how Aristotle conceives of rhetoric by way of dialectic. In other words, with all its emotive connotations, catharsis is profoundly a logical notion: ideally, playwrights of tragedy arouse and purge pity and fear under the aegis of reason. Of particular concern is the role of the rhetorical enthymeme (an informal syllogism) in achieving cathartic effect. Aristotle's endeavor to solemnize poetic creations thus crystallizes. This paper then clarifies the status of poetics in the Greek rhetorical tradition, expounds the relation of the Aristotelian tragedy to logic, and specifically explores the enthymematic reasoning that underlies catharsis. Such a rhetorical approach may contextualize Aristotle's catharsis in a historicized framework and supplement related studies that have long been confined to elusive interpretations such as purgation, purification, and clarification.