In ancient and medieval times, grammar concerned itself with correct language use through the study and criticism of literary models, dialectic concerned itself with the testing and invention of new knowledge through a process of question and answer, and rhetoric concerned itself with persuasion in public and political settings such as assemblies and courts of law. As such, rhetoric is said to flourish in open and democratic societies with rights of free speech, free assembly, and political enfranchisement for some portion of the population.
The concept of rhetoric has shifted widely during its 2500-year history. Today rhetoric is described more broadly as the art or practice of persuasion through any symbolic system, but especially language. Or, rhetoric can be described as the persuasive or "suasory" function of all human action, including symbolic action like language use. Both the terms "rhetoric" and "sophistry" are also used today in a pejorative or dismissive sense, when someone wants to distinguish between "empty" words and action, or between true or accurate information and misinformation, propaganda, or "spin," or to denigrate specific forms of verbal reasoning as spurious. Nonetheless, rhetoric, as the art of persuasion, continues to play an important function in contemporary public life.