The ninth book of Aristotle's Metaphysics — Book Theta — develops a theory of causal powers, and then distinguishes two ways of being: being-in-capacity and being-in-energeia (where energeia is, as a first gloss, the exercise of a capacity). The discussion culminates in a challenging and c... see more

This chapter considers how Metaphysics Theta presents its own project. Two topics are of special importance. First, it has been thought that Book Theta is to be read as a continuation or completion of Book Eta, which immediately precedes it. It is argued that this is a mistake. Second, Ari... see more

This chapter shows that the program Aristotle has set out for Metaphysics Theta begins with ordinary Greek. Energeia is set to one side, not being an ordinary Greek word but a made-up philosophical term. Another term, ‘dunamis’, takes centre stage, but only as it is used ‘in the preeminent... see more

This chapter analyzes the second chapter of Book Theta, which focuses on a certain important class of powers: those that consist in rational comprehension, referred to as rational powers. Such powers include the art of housebuilding and medicine. This characterization of rational powers is... see more

This chapter analyzes the third chapter of Metaphysics Theta, where Aristotle discusses the view of ‘certain people; for instance the Megarics’. Aristotle says that these people espouse a view about ‘can’ statements that sounds bizarre on first hearing: something can do something only when... see more

This chapter shows how in the latter part of Theta 3 and in Theta 4, Aristotle elaborates on the distinction between power and possibility, which played such a crucial role in his rebuttal of the Megarics. First, he focuses on possibility in its own right (Theta 3). Then he discusses the r... see more

In the sixth chapter of Metaphysics Theta, Aristotle resumes direct engagement with the science of being, as such. The entire text up to this point has been preparatory. He now undertakes, first, to explain being-in-energeia (Theta 6) and then the contrasting notion of being-in-capacity (T... see more

This chapter analyzes the passage of greatest importance for any interpretation of the notion of energeia: Theta 6. It is there, and only there in the entire extant corpus, that Aristotle undertakes to say as fully and clearly as he can what energeia is. The text is divided into three part... see more

This chapter comments briefly on a remarkable passage: 1048b18-35. The passage distinguishes two kinds of actions (praxeis): some are changes (kinēseis), others are energeia. It manages to have both of the following distinctions: it is one of the most discussed, and most often presupposed,... see more

This chapter analyzes Theta 7, where Aristotle shifts the focus of his discussion from being-in-energeia to being-in-capacity. The project of Theta 6 was to get us to grasp the concept of being-in-energeia. In the course of that discussion, we are to have seen the correlation between certa... see more

Theta 8 is the culmination of Aristotle's discussion of being-in-capacity and being-in-energeia, where he draws conclusions that constitute a contribution to the science of being. By the middle of Theta 7, Aristotle had carried out the program he announced in the opening lines of Theta 1: ... see more

This chapter analyzes Theta 9, focusing on three intimately connected concepts: that for-the-sake-of-which, the end, and the good. Theta 9 offers reasoned argument that eternal principles (if there are any) are perfect and that there cannot be any bad ultimate principles. Aristotle has fou... see more