A rhetorical system is an organized body of knowledge about communication. It consists of four elements: theory, teaching, practice, and criticism. Three great rhetorical systems arose to meet the communication needs of the people living during certain historical periods. The classical system dominated the intellectual world from about 500 BC to 1400 AD. the modern system developed from 1400 to 1900 AD. The contemporary system began about 1900 and is still developing today.
The classical system arose to meet the needs of the newly developing democratic societies in the city states of Greece. By focusing on the needs of the citizens to speak in court and in the public assembly, rhetoric became the art of persuasion through oral discourse. Because of limited information resources, rhetoric stressed the development of formulas, and prescribed means of discovering the materials for a speech such as the topoi or the stasis system. Classical rhetoricians identified and explained the various parts of the speech act , but their primitive understanding of psychology prevented the development of a sophisticated understanding of the relationship between the speech and the audience. Thus, we may characterize the classical system as using an oral medium, message focused, with a grammatical basis.
The classical system reached its fullest development in Rome during the late Republic when Cicero made it central to the cultural ideal of the orator-statesman. When Roman political power disappeared during the early Medieval period, the church took up the study and teaching of rhetoric to train priests. The form of the classical system survived, but the substance did not. As Medieval society gave way to the changes signified by the term, Renaissance, rhetoric had to meet the challenges of a new way of looking at the world posed by the rise of science and a new technology of communication, the printing press. Drawing upon new developments in science, rhetoricians now grounded rhetoric not in a grammar of the speech act, but in an analysis of the mind of listener/reader. The focus on the audience and the need to justify itself to science is characteristic of the modern system. We may say that the modern system uses a print/written medium, is audience centered, and is based on psychology.
The acceleration of scientific discovery and technological change characterizes our contemporary world. The invention of the electronic media transformed the communication environment by reducing the factors of distance and time. The combination of instantaneous communication, the rise of vast organizational structures both governmental and private, and ideological warfare on a world wide scale created a new communication environment. Increasingly in the twentieth century rhetoricians have focused on ways of overcoming alienation, discord, and division to bring people together. The extremely large audiences that can be reached through the mass media have forced rhetoricians to adopt the methods of sociologists and try to identify large social forces or trends that influence communication. The contemporary system uses the electronic media, focuses on human relations, and is sociologically based.