Should speakers prove their points?

Is it emotion, or logic, that makes the difference in public speaking? Many people think that emotion matters more than logic. George Lakoff argues that people make decisions on the basis of emotion, not reasoning. Centuries ago, Aristotle warned that emotional arguments could be irrelevant.

All the same, research has shown that persuasion based on evidence has longer-lasting effects than persuasion founded on pure emotion. Our feelings sometimes guide our sense of virtue and morality, which is good, but they also sometimes lead us to act on impulse or fear, which is bad. This is why I have always believed that the speaker's proof and evidence underlie most truly great speeches.

Larry J. Sabato, Kyle Kondik and Geoffrey Skelley recently commented  that we live in a post-factual era. Nevertheless, Aristotle and Thomas Jefferson said that truth is stronger than error, while Thomas Jefferson said that "error of opinion may be tolerated where reason is left free to combat it." In the long run, they will turn out to be right. Speakers should support their claims with evidence.