Distinct from prose essays as cultural expression, we use technical communication for functional purposes, addressing questions of how people learn as we craft our communications. Aristotle set out psychological principles of how people learn -- or are persuaded to change their minds -- when he laid down his foundational advice for rhetors to cultivate "the faculty of observing in any given case the available means of persuasion on almost any subject presented to us." Building on this foundational principle, technical communicators since World War II have studied how to achieve persuasion (or change) by making information accessible, formatting documents, writing at designated reading levels, and setting out instruction steps clearly. Recently, we have also become interested in how, through the concept of rhetoric, oral and written language acquires poignant social, ethical and technical dimensions, situating Aristotle's "faculties" of persuasion within specific cultural and political contexts.