The modes of persuasion are devices in rhetoric that classify the speaker's appeal to the audience. They are: ethos, pathos, and logos.
Aristotle's On Rhetoric describes the modes of persuasion thus:
Persuasion is clearly a sort of demonstration, since we are most fully persuaded when we consider a thing to have been demonstrated.
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 is so spoken as to make us think him credible. [...] Secondly, persuasion may come through the hearers, when the speech stirs their emotions. [...] 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.
Ethos (plural: ethe) is an appeal to the authority or credibility of the presenter. It is how well the presenter convinces the audience that he or she is qualified to present (speak) on the particular subject. It can be done in many ways:
By being a notable figure in the field in question, such as a college professor or an executive of a company whose business is that of the subject.
By having a vested interest in a matter, such as the person being related to the subject in question.
By using impressive logos that shows to the audience that the speaker is knowledgeable on the topic.
Pathos (plural: pathe) is an appeal to the audience’s emotions, and the terms 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 to appeal to fear, in order 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.
Logos (plural: logoi) is logical appeal or the simulation of it, and the term logic is derived from it. It is normally used to describe facts and figures that support the speaker's claims or thesis. Having a logos appeal also enhances ethos (see above) because information makes the speaker look knowledgeable and prepared to his or her audience. However, the data can be confusing and thus confuse the audience. Logos can also be misleading or inaccurate, however meaningful it may seem to the subject at hand. In some cases, inaccurate, falsified, or miscontextualized data can even be used to enact a pathos effect. Such as is the case with casualty numbers, which while not necessarily falsified, may include minor casualties (injuries) that are equated with deaths in the mind of an audience and therefore can evoke the same effect as a death toll.