The fundamentals of persuasion surely date back in their most rudimentary forms to our prehistoric ancestors. The capacity for speech introduced, of course, certain necessary refinements. Yet, argumentation wasn’t universally recognized as an art until the philosophers got ahold of it. Aristotle astutely classified three modes of persuasion in his classic text, On Rhetoric; his classical analysis corresponds surprisingly well with our modern models of argumentation. In other words, we can find ethos, pathos, and logos used in both evidence and warrants to support claims.
Of the modes of persuasion furnished by the spoken word there are three kinds… Persuasion is achieved by the speaker’s personal character when the speech was so spoken as to make us think him credible…
Ethos describes an appeal to authority or credibility. The authority of the presenter obviously lends to the persuasive power of his or her argument, but ethos can also be established by evidence.
EVIDENCE: Ethos aligns most closely with Social evidence. Examples include quotes from experts, endorsements from authority figures, or support from groups with high credibility regarding an issue.
WARRANTS: Ethos warrants work to establish the authority or credibility of a source of evidence. Examples include appeals to authority or generalizations connecting one credible group to a larger population.
Secondly, persuasion may come through the hearers, when the speech stirs their emotions…
Pathos describes an appeal to feelings or emotion. Any emotion, positive or negative, will do as long as it is strong. However, these appeals only work when the audience shares these feelings.
EVIDENCE: Pathos aligns most closely with Experiential evidence, in that effective personal anecdotes include emotional appeals. Examples include specific stories and descriptions of shared experiences.
WARRANTS: Pathos warrants work to inspire a certain emotional response to an argument. Examples include appeals to specific principles, sympathies, antipathies, fears, or desires. Also common are generalizations connecting an individual’s personal feelings or sufferings to a more universal experience.
Thirdly, persuasion is effected through the speech itself when we have proved a truth or an apparent truth by means of the persuasive arguments suitable to the case in question.
Logos describes an appeal to logic. Facts are extremely persuasive because they are, at least ostensibly, true. Arguments lacking logos often fail to persuade over the long term.
EVIDENCE: Logos aligns most closely with Factual evidence. Examples include citations of fact, figures, or research.
WARRANTS: Logos warrants work to establish both the indisputable nature of factual evidence and its relevance to the claim. Such warrants are critical because a given fact, accepted or not, may fail to support a point. Examples include logical reasoning, cause and effect relationships, and rational analogies.
Ethos, pathos, and logos manifest not only in substance but also in the style a speaker or writer chooses when delivering an argument: choose your words and tone deliberately. No argument should depend solely on one of these modes of persuasion. Instead, try to implement all three to ensure that your argument resonates on a logical, emotional, and authoritative level.