To properly understand Seneca’s philosophical writing, one needs to appreciate his sharp and often satirical wit. Any sensitive reader can observe that the Letters on Ethics, in particular, employs many standard humorous devices to lighten the tone and to hold the reader’s attention. Examples can be given of punning, incongruity, self-caricature, and more elaborate vignettes that recall the verse satires of Horace. But there are also instances in which Seneca’s humor is directed specifically at certain modes of philosophical speech and writing: the redeployment of Epicurean sententiae in letters 1–29; the cavillatio or trick syllogism of letters 45, 48, and 49; and the riff on Stoic metaphysics in letter 113. In these cases, one can best refer to the well-attested function of Roman invective humor as a means of policing boundaries. By them, Seneca communicates certain rules of generic decorum while also alerting readers to his own deliberate transgressions.