Near the end of his speech, Timaeus outlines a theory of bodily health and disease which has seemed to many commentators loosely unified or even inconsistent . But this section is better unified than it has appeared, and gives us at least one important insight into the workings of physical causality in the Timaeus. I argue first that the apparent disorder in Timaeus’s theory of disease is likely a deliberate effect planned by the author. Second, the taxonomy of disease in (...) the passage consists of one genus subsuming two species. Third, in Timaeus’s theory, health lies between perfect stability and a chaos of all possible motions; this indicates a conception of health as the activation of the body's powers in the right way. A power is a property directed towards bringing about some change. Fourth, the activation of these powers can change depending on the location of their possessors. This last point shows that causation among the physical items in the Timaeus involves structures as well as pushes. (shrink)