The dialogue begins when the eager young Hippocrates awakens Socrates before dawn to seek an introduction to Protagoras, the renowned teacher visiting Athens. Socrates agrees to accompany him to the house of Callias, where a distinguished gathering of intellectuals and disciples has assembled.
Upon arrival, Socrates questions Protagoras regarding what he intends to make of his pupil. Protagoras proudly asserts that he teaches prudence in private and public affairs, essentially the science of human life, and claims that virtue can indeed be taught. Socrates challenges this assertion by pointing out that the Athenian assembly allows anyone to speak on matters of statecraft, regardless of training, and that wise citizens often fail to pass their virtue to their sons.
In response, Protagoras delivers a famous myth about Prometheus and Epimetheus, explaining how Zeus distributed justice and reverence to all mankind so that cities could survive. He argues that the entire community acts as a teacher of virtue through education, laws, and the corrective nature of punishment, which aims at future prevention rather than mere retribution.
Following the speech, Socrates shifts the inquiry to the relationship between the virtues. Protagoras initially maintains that the virtues are separate parts of a whole, akin to the features of a face, with courage being distinct from wisdom, temperance, justice, and holiness. A lengthy debate ensues, featuring an interlude where the company discusses a poem by Simonides and the value of keeping discussions concise rather than delivering long, unbroken speeches.
As the argument resumes, Socrates subjects Protagoras’s views to rigorous dialectic. He challenges the notion that a person can act against their own best judgment due to being overcome by pleasure. Through careful reasoning, he argues that pleasure is the only good and pain the only evil, making moral failure a result of ignorance rather than weakness of will.
Finally, Socrates tackles the nature of courage, demonstrating through the art of measurement that true bravery is rooted in the knowledge of what is and is not truly terrible. By reducing the seemingly distinct virtues into manifestations of knowledge, the dialogue concludes with a paradoxical reversal: Socrates suggests that virtue is knowledge and therefore teachable, while Protagoras, who began by asserting its teachability, is left struggling to prove otherwise.
