Vincent Ferraro and Kathryn C. Palmer
Mount Holyoke College
South Hadley, MA 01075
Speaking and Arguing: The Rhetoric of Peace and War
A speaker should know his or her subject matter as thoroughly as possible. Depending on the sophistication of the audience, the speaker will relate information that is either widely known (in which case, the information needs little elaboration) or known to only a small number of people (perhaps to only the speaker). In this latter case, the evidence needs to be substantiated: how was it obtained? who obtained it? what are the credentials of the discoverers of the information? has the information been verified by others? can it be verified by others?
One should be extraordinarily careful never to confuse evidence or information with raw "facts." Facts tend to be evidence about which some people agree; those who disagree with the evidence deny that it constitutes a "fact." Indeed, one might be well-advised never to use the word "fact" in a speech. The term sets up the evidence as something about which there can be no disagreement and therefore excludes the audience from that part of the speech. Evidence is crucial, but evidence cannot explain itself. The statement, "The facts speak for themselves," is perhaps the most misleading phrase in the English language, and is itself a confession that the speaker has failed to make an argument. Evidence must be organized and interpreted if it is to be understood. Moreover, if someone persuasively disagrees with a speaker's "fact," the speaker runs the risk of having his or her credibility undermined.
Asserting evidence, however, should always convey the speaker's confidence in it. There is little reason to assert evidence about which one is uncertain; if the speaker is uncertain, why should the audience find the evidence persuasive? One should be careful to use only evidence that the audience believes can be verified through its own efforts or which has been vetted by knowable and reputable sources. Referring to sources which are closed to the review of others only works when the audience has already committed itself to a particular point of view (such as a statement by the Director of the Central Intelligence Agency to most members of Congress).
Making sure that evidence meets these criteria for substantiation is important because the criteria create a shared basis for what might be true or not true for both the speaker and the audience. Thus, evidence "proves" only that the speaker and the audience have certain understandings in common. The evidence must be made accessible to the audience and it must be credible to the audience. If the audience finds that the manner in which the evidence presented is consistent with its own understanding of the evidence, then it is likely that the audience will determine that the speaker is knowledgeable and therefore someone whose opinion can be trusted.
Evidence usually comes in three forms:
The speaker's personal experience. Information provided by personal experience performs two roles in a speech. First, it humanizes the speech by referring to something which many in the audience may have experienced as well. This immediacy is consistent with an overall objective of any speech--the desire to connect speaker with audience. Second, personal experience can only be illustrative, but its implications can be made very clear if the number of individuals or issues involved are limited. The problem with personal experience as evidence, however, is that it is usually not generalizable. One is talking about a single case, and it is never clear what a single case proves (usually nothing).
Empirical evidence. There are generally accepted forms of evidence which often require little explanation, but the degree of necessary explanation depends upon the criticality of the evidence. If, for example, one needs to assert something about the size of the American economy in order to make a point about its relation to other economies in the world, evidence from a U.S. Treasury document would need little elaboration or justification. However, if one is making an argument that the U.S. Government manipulates economic information in order to achieve certain social or political objectives, then a reference to that same Treasury document would require greater scrutiny.
Similarly, when information has been developed through well established procedures (such as in the natural sciences), there is usually little question about its validity. Names, dates, numbers, and other "hard" types of evidence are particularly effective when used judiciously. Nonetheless, one should be exceedingly cautious about how empirical evidence has been obtained and verified. The incidence of outright fraud in empirical evidence is rare, but not unknown. More likely is the manipulation of empirical evidence by institutions or groups that have a vested interest in particular conclusions from the evidence. We rightly regard as highly suspicious evidence about the health effects of second-hand smoke from the Tobacco Institute.
Authoritative opinion. Much of what a speaker might discuss cannot be found in his or her own personal experience or measured empirically. If others have written or spoken of their professional experiences, one can refer to that evidence. Similarly, if a scholar has devoted his or her life to the study of a particular issue and has published materials, one can use those published materials as a source of evidence. For example, the concrete evidence (names, dates, places, etc.) from Henry Kissinger on the matter of the U.S. opening to China in 1973 would be highly credible, even though the speaker may not know Henry Kissinger or has never been to China. However, Kissinger's opinions on the usefulness or necessity of the opening to China would be highly suspect (but not automatically dismissable) since he had a vested interest in the success of the move. One should be careful about the use of authoritative opinion. One should remember that opinions are nothing more than that. One should make sure that the opinions cited are indeed "authoritative."