The question of evil comprises an important theme for Plato. Evil takes root in wrongful acts—those which by nature involve shame and/or pain. Not only is this position argued in Gorgias by Socrates, but the other participants in the conversation agree with him as well. This aspect of evil exists as one of the text's few uncontroversial claims.

Dissention enters instead with the discussion of what is the greatest evil, or which is "worse": to suffer or to inflict wrong (e.g. 473a). On the one hand, Socrates's opponents (mainly Polus and Callicles on this issue) state that suffering wrongdoing is worse, since it places the sufferer in a position of pain and subjugation to the inflictor. On the other, Socrates maintains that committing wrong is worse, since it is more shameful and therefore painful and evil. He goes on further to declare it worse still to inflict wrong without being punished, since retribution for an evil act at least helps to right the wrong.

Such considerations are integral to Plato's purpose within the dialogue, because wrong and evil relate directly to its other key topics: the inquiries of art, justice, politics, virtue, and temperance center around what is right and wrong conduct within each field of focus. The notion of evil also is important within the scheme of Plato's overall body of work. This is so at least in large part due to the death of his virtuous teacher at the hands of an apparently evil government. For Socrates not to have died in vain and supreme evil, nor to leave behind a legacy of error, such definitions of wrong must prove convincing. As a consequence of this fact alone (independent of his general and powerful interest in the philosophical character of right and wrong), the nature of evil constitutes a recurring theme of Plato's philosophy.