To begin with, I would use an example of something that happened in my life or someone else's life to show that my case is applicable. Although this does show more feeling than logic typically, it really amplifies what I am trying to point out. Then, I might use statistics, and definitely a demographic, whether asking the audience to raise their hand if X, or audience analysis like a survey given to the audience. You probably have crossed the line when you are trying to make them believe what you believe.
Chapter 3 Response
Logic VS. Feeling - Spears
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