In the Timaeus, human bodies are treated as homeostatic systems, striving to maintain their natural state. This striving constitutes Plato’s explanatory framework for perception: perceptions come about when the equilibrium is shaken, and when it is restored. The article makes two main suggestions: first, that experienced pleasure and pain are grounded in non-experiential departures from and restorations of the natural state. Second, that the striving to maintain the natural state grounds perceptual interests, especially through conscious algesic and hedonic affection. Explanation (...) of what humans find desirable and avoidable in their environment – what they attend to – is a complicated story that in the context of the Timaeus must include the role of human rational abilities. This article, however, only sheds light on its other, very basic aspect: the teleology involved in bodies and how it affects perceptual interests. (shrink)