  Predications indicating that something is not strictly speaking in the subject but nonetheless in it in some way can be of two sorts. One involves a cause of an action. For example, in ‘Socrates is teaching,’ ‘Socrates’ refers to the cause of the action of teaching, and therefore accounts for the ninth category, action [agere]. The other involves being affected by an action. For example, in ‘Plato is being taught,’ ‘Plato’ refers to the recipient of the action of teaching, and therefore accounts for the tenth category, passion [pati].