Aristotle identified the productive sciences as those concerned with the making of things, such as farming, art, and engineering. Aristotle did not say much about productive knowledge. The practical sciences are concerned with action and with how we ought to act in various circumstances, in both private and public affairs. Knowledge becomes theoretical when its goals are neither production nor action but simply truth, and this is what we now think of as science. For Aristotle, this truth contained by far the greatest part of the sum of human knowledge. Aritotle then divides this subject into three species, meaning the theoretical philosophies of mathematics, natural science, and theology.
Rhetoric is also linked closely to the field of logic, and Aristotle expresses this link when he examines language and expresses the view that he is "interested only in sentences that are true and false (commands, questions, exhortations, and the like are the concern of the student of rhetoric or linguistics). He holds that every such sentence is either simple or else compounded from simple sentences; and he explains that simple sentences are those which affirm or deny something of something -- some one thing of some one thing, as he later insists" (Barnes, 2000, p. 46). Aristotle sees rhetoric as part of the search for truth, and in this reagard it fits clearly with the work of a court of law, which is also directed ast finding the truth.
One way of doing so is through the application of logic, and, as noted, rhetoric is closely allied to logic. Rhetoric is also the art of persuasion, properly achieved through the application of logic over emotions, and rhetoric in the courtroom has a particular role as a persuasive device, using language and logic to make an argument and to shape a story in order to persuade others. To achieve this, the individual may use elements that are both enthymemic (meaning deductive) and inductive, arguing by example. Both are common in the rhetoric of the law. Arguments in court can be both ethical arguments and arguments by example.
The ideas expressed by Aristotle would help shape ideas about rhetoric, politics, and law for generations. Cicero was a follower of Aristotle, for instance, and Cicero's works are also important because they serve as a link between the theirs of Aristotle in the Greek world and later generations, carrying ideas through the Hellenistic age which otherwise would be lost to us: "They furnish, accordingly, some notion, incomplete to be sure but nevertheless valuable, of the ideas about government which passed from Greece to Rome in the three centuries before the Christian era and produced such profound effects upon Roman law" (Cicero, 1976, p. 40). In addition, Cicero's works contain the germs of ideas that would be developed during the imperial age by the great jurists and which would appear later in the teachings of the Roman lawyers of Bologna and in the early political theories of the Middle Ages.
Ciero would influence St. Augustine in the Middle Ages. Before converting to Christianity, Augustine was a teacher of rhetoric. Augustine's most important contribution was to revive interest in rhetoric within the new Christian tradition after the early Christians had foresworn rhetoric as a pagan art. St. Augustine embodied rhetorical concepts in his writings and teachings and argued that preachers needed to be able to teach, to delight, and to move, the same notions of the duties of the orator held by Cicero. Augustine said that to accomplish the aims of Christianity it was necessary to pay attention to the rules of effective expression. He also said that such rules were to be used only in service of the truth and so revitalized the philosophic basis of rhetoric (Bizzell & Herzberg, 1990, pp. 382-383).
The application of rhetoric and rhetorical analysis to politics and law both should be obvious, and Aristotle made both explicit in his writings on the subject. Others would extend what he said as they analyzed and affected the development of political and legal traditions from that time to this.
Aristotle. From Rhetoric. In P. Bizzell & B. Herzberg, the Rhetorical Tradition (Boston: Bedford Books of St. Martins, 1990), 155-194.
Barnesl J. (2000). Aristotle: A Very Short Introduction. Oxford: Oxford University Press.
Bizzell, P. & B. Herzberg (1990). The Rhetorical Tradition. Boston: Bedford Books.