Plato's views about psychology in the later dialogues, such as the Laws, just as in the middle-period ones, such as the Republic, are tightly connected with other important aspects of his philosophy. An individual's character, virtuous or otherwise, is essentially constituted by the content, structure, and ways of regulating his knowledge, beliefs, emotions, desires, pleasures, and so on. Plato's understanding of these items will thus shape many aspects of his views on education, ethics, and political community. But Plato's understanding of these items also will constrain and be constrained by his epistemology and metaphysics.
The main issue that I discuss here is how Plato conceives of non-rational motivations – such as appetitive desires, some kinds of desire for sensory pleasures, anger, fear, and so on – and how he understands the relations among them and the person's reason. In previous work, I have argued that Plato's psychology in the Laws and other late dialogues differs significantly from that of the Republic. Here I want to consider some worries that have been raised about this account. I begin by noting, without arguing for them here, my earlier claims that are most relevant to the topic of non-rational motivations. Famously, the Republic divides the soul into three parts: the Reasoning part, the Spirited part, and the Appetitive part. This account holds that in the Republic:
1 the three parts of the soul are the ultimate subjects of psychic items, such as beliefs, desires, emotions, and so on;
2 all the parts have contentful beliefs and desires and this content is, at least partly, conceptual;