However, the fact is that your audience will often be unpredictable because of its mood or prevailing emotional disposition, and one must learn how to handle emotions, both yours and theirs. Aristotle discusses an audience's "disposition" in The Art of Rhetoric and compels the reader into believing his argument, which is that "shameless emotionalism" is "not rational" and is unworthy of being aligned with the practice of rhetoric. In fact, you will lose your audience if you sound irrational or unwilling to compromise, or if you are blatantly manipulative, or use "god terms", designed to inflame or provoke. ("God terms" is a phrase conceived of by rhetorician Richard Weaver, of the University of Chicago. In The Ethics of Rhetoric, Weaver said that "god terms" are words particular to a certain age and are vague, but have "inherent potency" in their meanings. Such words include 'progress' and 'freedom,' words that seem impenetrable and automatically give a phrase positive meaning.)
An ethical use of rhetorical practice is defined, therefore, by adhering to certain rules when using emotion. Emotions should not be manipulated. Touching someone's heart with your honest feelings about something is permissible, but deliberately provoking a strong emotional response in the listener by playing on their guilt is considered manipulative and wrong. The power the speaker has over the masses, Plato believed, is considerable. The speaker (or writer) who can compel his or her audience to action, or a change of heart or belief, obviously has considerable real-world power, and Plato feared this power would be misused by unethical orators.
In today's world, think of how often you feel manipulated by a political speaker, for example. How often do you feel strongly about an issue you've seen presented on television, when five minutes before, you might have been calm, eating dinner or reading a book? Somewhere in those few minutes, you overheard words that compelled you to feel differently than you had just a few minutes before--that's the power of rhetoric. Therefore, it is the responsibility of the writer or speaker to be certain that their words stem from the highest motives, otherwise your use of emotion will be considered unethical and manipulative, and will most likely alienate your audience. Audiences are very astute; they've heard millions of words during the course of their lives, and they usually know when they are being deceived.
This is not to say that one should attempt to "rise above" emotion. That is a common fallacy that people believe, because of the prejudice against irrationality we have inherited from the Western philosophical tradition. There is little value in ignoring emotion and pretending your audience (and you) have no feelings. All human beings are motivated by their feelings at all times; what differs from person to person is the ability they have to control their feelings, understand them, and use them responsibly. To try to ignore your feelings when constructing an argument is futile. You're human. You feel. It's normal! And in fact, your audience will respect you more, and give you more credibility, if you can show why your feelings are controlled, yet germane to the issue at hand. One has respect for those with obvious self-control who are also obviously compassionate and understanding.
Emotions underlie one's argument at all times. The goal of effective rhetoric is never "to win," however, which is why abusing the privilege of touching your audience is not morally or ethically fair. The goal of effective rhetoric is to get your audience to see your issue from your perspective, and to get them to think the way you do, if only for a minute. Once you realise and accept how incredibly difficult it is to change anyone's mind about an issue that matters to them, that they have formed strong opinions about, you will understand why it's so important you use your emotions, not to control or manipulate others, but to persuade them that your feelings about the subject you're speaking about make sense, and are fair and right.
There is nothing wrong, ironically, with using your honest emotions to convince your audience of the importance of your point of view. The only thing that's ever wrong about relying on emotion when speaking or writing, is if you misunderstand your audience's disposition, and assume they feel something they do not, or agree with you when they do not. Then you most likely will have lost ground, and will not present an effective argument. Therefore, it is imperative that you pay close attention to the mood of your audience, and try, at all times, to gauge ahead of time what their mood is likely to be. Since their beliefs about your argument might not yet be fully formed, you have the opportunity to persuade them to see your position; use this opportunity with sensitivity, compassion and awareness that the people in your audience all come to hear you (or read what you have written) with their own feelings about the matter. Your words might trigger some deeply-held belief (or prejudice) of their own, and you, as an effective rhetor, must know enough about their beliefs to counter their potential disagreement with an appeal that they can hear.
Remember that most audiences are sincerely open to hearing you, but they will shut off if they feel offended, insulted, patronized, or lied to. Therefore, bring your honesty to your speech or piece of writing, and know that your emotions can be extremely powerful tools to help you convince your audience to feel just as strongly as you do about your subject. Never feel like you are forced to hold back how you really feel; just make sure you express yourself with respect for your audience's sensibilities. This creates the most powerful speech of all: one that combines effective use of logos, ethos, and pathos. I have said many times to students that a piece of writing, or speech, that relies too heavily on any one of these proofs is destined to fail, but a speech that relies on each one in balance is almost inevitable destined to persuade your audience of the essential correctness of your argument.
So, never leave pathos (the appeal to emotions) out of your argument, wrongly thinking you must, at all costs "sound rational." An over-reliance on logos (appeal to reason or logic) will lose the audience that came to hear a powerful speech, just as surely as lying to your audience in any way will make them doubt your credibility. Since your credibility can be enhanced by effective use of emotion, never fear that your emotions are somehow 'wrong,' just because we've been taught to discount them in Western society. Your emotions give power and resonance to your argument, when used with sensitivity to your audience.