In “Plato's Pharmacy,” Derrida demonstrates the way in which the ambivalent signifier pharmakon, meaning both poison and medicine, deconstructs the opposition between speech and writing that subtends the Phaedrus. That opposition, in turn, is based upon an even more fundamental one between internality and externality (Derrida 1981: 103). Speech is the reflection of truth because it emanates from the inside and is directly present to consciousness. Writing is secondary and derivative, existing as an externalization of a prior moment of interiority, i.e., thought as silent speech (Stoekl 1992: 201). The deconstruction of the priority of speech over writing, through the latter being characterized as a pharmakon and hence as both a salutary healing agent and a foreign noxious other, is itself a deconstruction of the priority of truth over its external and derivative manipulation through formalized practices of speech and writing: i.e., rhetoric. Rhetoric as a practice is associated throughout the Platonic corpus with the sophists and is generally opposed to philosophy defined as the pursuit of truth. Derrida in his deconstructive reading of the opposition between speech and writing in the Phaedrus demonstrates that, in effect, Plato himself deconstructs the opposition between rhetoric and philosophy through the deployment of philosophy's initial, constitutive trope, Socratic irony, as figured by the duplicitous pharmakon. The result is that rather than philosophy and sophistry being mutually exclusive alternatives, each becomes a moment within the other, which can never be fully sublimated. Philosophy on this view, I contend, is less a policing of the borders of discourse than a series of persuasive interventions in the ongoing dialogue that constitutes the movement of truth in time.