Phaedrus and Socrates discuss whether a speaker must be knowledgeable about his subject to be persuasive. Phaedrus has heard that a speaker simply needs to express his ideas with conviction to be persuasive, but Socrates disagrees. Phaedrus agrees to debate Socrates’s arguments to the contrary one at a time.

Socrates gets Phaedrus to agree that rhetoric is the art of winning a “verbal contest,” whether such a contest takes place in a courtroom, in a political speech, or in private conversation. In all cases, an effective speaker will be able to convince his audience to do what he wants, regardless of whether such an action is actually right or wrong, or whether his case is truly just or unjust. If a speaker wants to deceive his audience, Socrates asserts, he must know the truth about the matter, in order to make his argument seem reasonable and to avoid being detected by his audience. Thus, he concludes, one who does not know the facts about his subjects will fail as an orator.

Socrates suggests that they use Lysias’s speech, which Phaedrus read at the beginning of the dialogue, as a test case for these ideas about rhetoric.