 Theoretically, argumentation theory incorporates three approaches to argument that have been associated with logic, rhetoric, and dialectics since ancient times. Logic understands an argument as an attempt to justify a conclusion, emphasizing its probative or epistemic merit. Rhetoric treats an argument as an attempt to persuade, emphasizing its persuasive force. Dialectics understands an argument as an element of an exchange between interlocutors with opposing points of view, emphasizing its place in an interaction between arguers who argue back and forth. 