Pathos is persuasion through the audience's emotions — one of Aristotle's three modes of appeal, alongside ethos and logos. It is not a figure of speech but a ground of persuasion: the choice to move an audience rather than to inform or impress them.
It is also the mode most often mistaken for a fault in itself, which it is not.
Antony over Caesar's body: “If you have tears, prepare to shed them now.” He then shows the crowd the mantle and the wounds. The evidence is real; the use made of it is entirely emotional.
Aristotle treated pathos as a legitimate and necessary mode of proof, not as a lapse from logos. The modern suspicion of emotional appeal is a later development.
Becomes Appeal to Emotion when feeling replaces the evidence entirely.
Emotion is not the opposite of reason in argument, and treating it as such produces bad analysis. Many claims are about things that matter to people, and conveying why they matter is part of making the case accurately. A description of a famine that produced no feeling would be a worse description, not a more rigorous one.
The distinction that matters is whether the emotion is proportionate to the evidence and derived from it. Pathos grounded in something true is a way of helping an audience grasp the weight of what is being claimed. Pathos substituted for evidence is a way of preventing them from asking what the claim rests on.
The practical test is subtraction. Remove the emotional content and see whether an argument remains. If what is left is a case that the feeling was helping convey, the pathos was doing legitimate work. If what is left is nothing, the feeling was the argument.
