The modes of persuasion, often referred to as ethical strategies or rhetorical appeals, are devices in rhetoric that classify the speaker's appeal to the audience. They are: ethos, pathos, and logos.
Aristotle's Rhetoric describes the modes of persuasion thus:
Ethos (plural: ethea) is an appeal to the authority or credibility of the presenter, as well as the moral values that the members of the audience share in relation to the subject of the presentation or conversation. If the presenter knows or assumes that the members of the audience share certain moral values, the presenter then can appeal to those values to support their idea. To do that, the presenter must demonstrate how their idea agree, promote, or connect to those moral values. It is also how well the presenter convinces the audience that the presenter is qualified to speak on the subject. This can be done by:
Pathos (plural: pathea) is an appeal to the audience’s emotions. The terms sympathy, pathetic, and empathy are derived from it. It can be in the form of metaphor, simile, a passionate delivery, or even a simple claim that a matter is unjust. Pathos can be particularly powerful if used well, but most speeches do not solely rely on pathos. Pathos is most effective when the author or speaker demonstrates agreement with an underlying value of the reader or listener.
In addition, the speaker may use pathos and fear to sway the audience. Pathos may also include appeals to audience imagination and hopes; done when the speaker paints a scenario of positive future results of following the course of action proposed.
In some cases, downplaying the ethos can be done while emphasizing pathos, for example as William Jennings Bryan did in his Cross of Gold speech:
I would be presumptuous, indeed, to present myself against the distinguished gentlemen to whom you have listened if this were but a measuring of ability; but this is not a contest among persons. The humblest citizen in all the land when clad in the armor of a righteous cause is stronger than all the whole hosts of error that they can bring. I come to speak to you in defense of a cause as holy as the cause of liberty—the cause of humanity.