READING the letters of Heloise might be compared to coming face to face with a basilisk. The text, like that mythical beast, both fascinates and paralyzes us, holds our gaze even as it resists our attempts to gain the upper hand. (1) That mixture of enthrallment and frustration, tempered with the crippling inability to attain a concrete meaning, is probably familiar to many readers of this famous 12th century French intellectual's correspondence with her husband and former teacher, Peter Abelard. It is also, at least to some extent, the result of a specific rhetorical strategy on Heloise's part. As Peggy Kamuf has demonstrated, Heloise's letters stage a "breakdown of [the] structure of opposition" on which both language and logic are based (44). Heloise creates extended metaphors and builds arguments around opposing pairs of concepts, only to destabilize or destroy the putative differences on which these oppositions are based. Self-fulfillment and self-destruction, marriage and concubinage, chastity and licentiousness, religious devotion and blasphemy, are just a few of the opposing pairs that, as Kamuf shows, Heloise blurs, "displaces" or "reverses" in her letters (13). Kamuf's insight is particularly apt because it reminds us that logic--the medieval "art of speaking truly" is structured around a cluster of basic oppositions. (2) As the prize pupil of the most important logician of her day, Heloise would have been acutely aware that oppositions are the building blocks of reason, and indeed of meaning. This article will examine Heloise's use of what is for her a particularly crucial opposition, that between hypocrisy and sincerity. (3) In her letters, Heloise repeatedly examines her own sincerity and hypocrisy, ultimately refusing to decide between the two and embracing the identity of the "sincere hypocrite." Heloise's dismantling of the sincerityhypocrisy pair is an example of the rhetorical strategy that Kamuf has described, but I believe its particular interest lies in the light that it can shed on the construction of Heloise's authorial persona. By simultaneously calling attention to her own sincerity and casting it into doubt, Heloise also privileges and interrogates the link between self and words. Her discourse of sincere hypocrisy draws readers towards an imagined author even as it suggests that this seductive figure may be unreliable and illusory. In this case, the basilisk facing readers of Heloise's letters turns out to be the paradoxical authorial persona of Heloise herself.