Gorgias refers to the last dialogue that Plato wrote before leaving Athens. It features Socrates and Gorgias participating in a microcosm of the sophist-philosopher debate that raged throughout ancient Athens. Whereas the sophists were relativists who believed that rhetoric was a useful tool that could exploit the imperfection of human knowledge, Plato and the philosophers proposed the existence of a transcendental, perfect knowledge. In order to access this higher truth, philosophers utilized the practice of dialectic. Rhetoric, Plato asserted, was a perversion of dialectic that harmed the soul by creating false belief.
It is in this dialogue that Plato offers one of the most famous critiques of rhetoric, calling it a "ghost or counterfeit of a part of politics" and a form of "cookery." In labeling rhetoric a form of cookery, Plato draws an analogy between care for the human body and the management of politics in a society. Just as a doctor uses medicine to heal and protect the body, philosophers can utilize dialectical reasoning to arrive at just decisions that benefit the entire polis. Like a tasty but unhealthy dish, rhetoric delights the common people (or "demos") into pursuing short-term desires at the expense of long-term justice.
The purpose of politics being to establish justice and virtue throughout the whole of society, Plato believed that rhetoric, through its creation of falsehoods, was the root of evil in the Athenian state. His opinion of rhetoric was the logical corollary of his belief that ordinary people did not have the aptitude to govern wisely. This sentiment also formed the basis for his masterpiece The Republic.
Callicles provides an effective foil to the role of the professional philosopher. He asserted that the business of serious people, read aka adults citizens, was serious affairs and not the idle discussion of philosopher. Much like Wittgenstein's call to graduate students to drop out.