I argue that it is in the philosophers’ best interest to rule Kallipolis because that life is the best available to them. Although the life of pure contemplation of the Forms would make them happiest, I make the case that, on Plato’s view, this life is not an option for them because of the essential psychological connections that he posits between the individual and the city. To make this argument, I first draw on Plato’s city/soul analogy to explore why it is in reason’s best interest to rule the soul. The answer, I claim, rests in the interconnectedness of the three parts of the soul. If reason does not rule the soul, Plato says that reason will be ruled by another part of the soul and will be forced to serve the ends of the ruling part, which is worse for reason than ruling the soul. Similarly, the philosophers must rule or be ruled. I argue that, as we would expect from the city/soul analogy, Plato thinks that it is worse for the philosophers to be ruled by another part of the city than to rule Kallipolis. This is because, on Plato’s view, individuals internalize their culture, and if the philosophers do not rule, they internalize an unjust culture, which adversely impacts their ability to contemplate the Forms. However, if the philosophers rule Kallipolis, they internalize a just society, which best facilitates their contemplating the Forms. The upshot is that, due to the interconnections that Plato sees between psyche and city, he thinks that ruling Kallipolis is the best option available to the philosophers.