I. The parts of rhetorical discourses have functions that relate to three traditional means of gaining assent.
A. Reason. Here the speaker proposes rational relations among assertions with a view toward gaining audience adherence to the claim or claims offered. Toulmin's theory of argument presents a model for the operation of this direct means of gaining assent. Specifically, the speaker presents a "claim" for acceptance by the audience. As rational support for the claim, the speaker offers "data." The relation between the "data" offered by the speaker and the speaker's "claim" is justified by a "warrant" or inference rule. The "warrant" permits the speaker to reason from the "data" to the "claim." The "warrant" is an abstraction from "backing," i.e. some set of foundational principles. Arguments seem reasonable to audiences if the speaker refers to "data" and resorts to "warrant" which are acceptable to the audience addressed.
B. Character. Here the speaker characterizes himself or herself or some other person. The idea is to create expectations or probabilities of behavior. Traditionally, the speaker is supposed to show through the discourse that he or she has good sense (prudence), good morals (virtue), and good will (friendship) toward the audience. The expectation, once the speaker has shown these things, is that the speaker will propose wise claims, speak truthfully, and try to help the audience. This too is a direct means of gaining assent.
C. Emotion. Here the speaker arouses emotional states in the audience, then uses these emotional states as "alternate contexts" for evaluation of rational and perhaps character appeals. Although emotional states may be aroused by non-rational means, the easiest and most predictable way of arousing audience emotions is by creating a belief in the audience that is causally linked with a subsequent emotional state. For example, if a speaker gets an audience to believe that Jones is intentionally thwarting their efforts, a natural outcome is for the audience to become angry with Jones. Obviously, the audience will process rational and character appeals differently when they are in different emotional states. This is an indirect means of gaining assent, because creating an emotion does not in itself secure belief or attitude.
II. What constitute the "standard" parts of a speech differs by culture and time period; in American speaking it is usually informative to begin with the expectation that the speech has three parts--introduction, body, and conclusion.
A. Introduction. The traditional functions of speech introductions are to render the audience attentive, benevolent, and intelligent (with regard to the content of the speech).
1. Obviously, audience attention is needed so that the speaker can use the speech to gain audience adherence to the speaker's claim. To gain attention, the speaker may resort to rational appeals; e.g., audiences attend to discussions of matters that the speaker has proven important to their interests. The speaker may also resort to character appeals; specifically, a speaker may rely on a sense of wisdom, virtue, or friendship to get the audience to attend to what he or she says. Presidents use their powerful role to secure attention and cultural heroes, e.g., Colin Powell or Cal Ripkin Jr., have an attentive audience whenever they speak. Finally, the speaker may arouse emotions to secure attention. For example, a speaker might tell part of a story at the beginning of the speech in order to get the audience to attend long enough to hear the end of the story.
2. A benevolent hearing of the speaker is one where the audience interprets what the speaker says in a light favorable to the speaker and/or unfavorable to the speaker's opponent. To secure benevolence the speaker may have to erase prejudice against himself or herself or against his or her cause. Again he or she may want to create prejudice in favor of himself or herself or his or her cause. Likewise, the speaker may also try to erase prejudice in favor of an opponent/cause or create prejudice against an opponent /cause.
3. The audience is rendered intelligent with regard to the content of the speech by preview or foreshadowing.
B. Body. The body of the speech conveys the speaker's most concerted attempt to gain adherence to his or her claim. It always contains an argument and sometimes contains a narration.
1. Narration. Narration is a speech element designed to represent the facts of a case in a way that is favorable to the operation of the speaker's argument about that case. It is most useful in legal or quasi-legal situations, since within such situations the audience makes a judgment about what happened in the past. Still, narrations can also be used in other kinds of speaking, especially to establish the context for the speaker's contribution to an ongoing debate. Narrations may involve rational appeals insofar as they attempt to get the audience to believe in certain circumstances on account of the "data" of the narration. They may also create conceptions of character in the audience's mind, since the audience attributes the presence or absence of wisdom, virtue, and good will to persons based on how they are depicted as behaving in narrations. Narrations may also create emotions in the audience, since the audience responds to the situations depicted as if they were happening in front of them.
2. Argument. The argument of the speech represents the speaker's attempt to reason with the audience in a way that secures audience adherence. Still, within an argument the speaker may rely on character to get the audience to accept certain assertions. Moreover, the speaker may create emotional contexts for the audience's reception of segments of the argument or even the entirety of the argument. For example, a prosecutor arguing for capital punishment may attempt to arouse anger or indignation in a jury to get a more favorable reception of his or her reasoning that capital punishment is justified.
C. Conclusion. The conclusion of the speech must reinforce the speaker's point of view. Its traditional functions include recapitulation, refreshment of benevolence, and arousal of audience emotion.
1. Recapitulation reminds the audience of the speaker's reasoning.
2. Refreshment of benevolence attempts to consolidate any audience prejudice in favor of the speaker and his or her cause and against any opponent and his or her cause.
3. Arousal of the audience may refresh emotions already created or create new emotions. New emotions might be needed to get the audience to accept some ultimate belief or attitude. For example, in a religious speech a new arousal of emotion might be needed to heighten motivation for audience members to convert to the faith proposed in the speech. Otherwise, new emotional arousal might be used by the speaker to ensure audience memory of the speaker's point of view; for generally, audience's recollect positions better if they have emotions coupled with those positions.