Discussions on what rhetoric is and who needs it and why are noteworthy issues in the history of philosophy. While thinkers before Aristotle saw rhetoric as a form of speech that helps manipulate the audience only by activating their emotions, Aristotle structures it as an art needed by every human who deals with the act of persuasion in some way. This structuring consists of three elements as speaker, reasoning, and audience, and three persuasion styles as speaker's character, reasoning, and the emotional state of audience. The centrality of reasoning in this structuring clearly reveals the originality of what Aristotle did. Since the art of rhetoric, as structured by Aristotle, aims to persuade with reasonable justifications, every human in some way needs this art not only persuade the people he speaks to but also to protect himself from manipulative speeches.