Plato’s critics observe that he tells us little about the sphere of the oikos in the Kallipolis. Even whether there would be slaves is contested. Vlastos suggests that they are a fourth class doing all the unseemly work behind the scenes. Yet, even though the text mentions slaves in passing, a fourth class doesn’t fit into the psychodynamic taxonomy of the Kallipolis, which has led to the suggestion that, to be consistent, Plato’s Kallipolis shouldn’t have slaves. Neither of these positions is satisfactory. Rather, the economic arrangement of the Kallipolis leaves no room for a distinction between trader-producers and their putative slaves. The household disappears both as a political and an independent economic unit, removing the conditions under which there could be intra-household literal slavery or inter-household metaphoric slavery, although Plato’s aristocratic economic dirigisme means that in no way should he be thought of as an abolitionist. Rather, Plato thinks of the worker class as either slaves or slavish, but objectively freed because they are ruled by reason.
Hyde, Tim, "Reasonably Free: The Question of Slavery in Plato’s Kallipolis Revisited" (2009). The Society for Ancient Greek Philosophy Newsletter 2008-2009. 1.