When truth is manifestly clear, when self-evidence leaves no room for willful choice, all rhetoric is superfluous.
On the other hand, when the thesis is shown to be arbitrary and there is no reason to favor it, the demand for submission
to a constraining power can come about only through brutal force, without any concern for intellectual acceptance.
These two extremes are indeed rare; the field of rhetoric is thus immense.
Chaïm Perelman

Contrary to the common conception of rhetoric as either the art of deception or a lofty style of speaking, rhetoric is a broad field that primarily studies the means of persuasion in situations of contingency, where complete truth is neither self-evident nor arbitrarily imposed by violence. As Chaïm Perelman notes in the passage above, because few conclusions are so self-evident or arbitrarily imposed that they're beyond the need of persuasion, rhetoric is an immense field of inquiry. It includes the study of the available means of persuasion in particular situations as well as whether or not persuasion is possible in particular situations, why particular persuasive appeals succeed or fail, and the relationship between persuasion, coercion, and violence. Kenneth Burke argues that rhetoric is rooted in an essential function of language—the use of language to induce cooperation in beings who by nature respond to symbols. While rhetoric includes the study of nonverbal communication, it often focuses on the use of language and specifically symbolic exchanges.

Legal scholar James Boyd White has argued that the lawyer is “the modern rhetorician in its purest form.” Lawyers are among the most familiar figures of public argumentation and assume a unique role of arguing from particular cases in our society. This function of lawyers is particularly important for a consideration of rhetoric, which has always distinguished itself by considering particular situations, audiences, and cases rather than universal notions of truth. My research focuses primarily on forensic rhetoric, including not only legal rhetoric as the paradigmatic form of forensic rhetoric but also legalism in its many broader forms. I particularly study the role of narrative, memory, and proof in discourse about the past, the use of evidence in persuasive discourse, writing and argumentation about normative claims, and the relationship between the adversary system of justice and society’s attitudes toward the resolution of disputes.

You can read more about my research interests on the Research and Publications and Papers pages. The Rhetoric and the Law page outlines a rhetorical theory course I’m teaching at the University of Texas at Austin this spring and summer and during the 2012-2013 academic year.
 
You can contact me at dmcoulson@msn.com or via Twitter.