In this engaging book, Kosman offers a vigorous extended defence of a distinctive and highly ambitious claim, namely, that Aristotle’s account of potentiality/ability and actuality/activity in book Theta of the Metaphysics is an integral and central part of Aristotle’s account of what being is, which means that, for Kosman, Aristotle defends the thesis that being is, precisely, activity. In addition to the distinctive character of this claim, there are two notable suppositions behind it, which, likewise, Kosman defends. First, the Metaphysics (...) is addressed to a single, overall question, namely ‘What is it for something to be?’, a question that Aristotle introduces in book Gamma, takes on in books Zeta and Eta, gives a distinctive answer to in Theta and takes to its point of culmination in Lambda. This question, as Kosman spells out instructively and at length, is tackled by Aristotle through a distinction between primary being, or substance , and other beings .. (shrink)

Aristotle notoriously begins his examination of being in the sense ofdunamisandenergeiainMetaphysicsTheta with what he describes as the sense that is ‘most dominant’ but not useful for his present aim. He proceeds to define the not-useful sense ofdunamisas “the principle of change in something else or in itself qua other”, along with other senses derived from this primary sense. But what then is the useful sense? All that Aristotle tells us at the outset is that it is a sense that extends (...) “beyond things spoken of only in relation to motion” and nowhere in Book Theta does he explicitly identify the useful sense as such. This has allowed for very different interpretations of the useful sense in the literature, the primary ones being that it is (1) ‘possibility’, (2) the potential to receive a form, (3) being-potentially-x understood modally as encompassing all specific senses ofdunamis, and (4) capacity for substantial change. The present paper argues that there are significant problems with all of these suggestions and defends an identification of the useful sense ofdunamiswith the sense that Aristotle explicitly opposes to the not-useful sense at the start of Theta 8:phusis(‘nature’). This goes hand-in-hand with an identification of the useful sense ofenergeiawith ‘activity’ as distinguished from motion/change at the end of Theta 6. What makes these senses ofdunamisandenergeiathe useful ones for Aristotle’s present aim is that they are required to explain fully the priority ofenergeiatodunamisin substance defended in Theta 8, they support the identification in Theta 9 ofenergeiawith the good, and they explain the unity of the only substances that Aristotle recognizes as being genuinely substances: natural living substances. (shrink)

_ Source: _Volume 60, Issue 1, pp 88 - 126 The dominant interpretation of Metaphysics Θ.8 commits Aristotle to the claim that the heavenly bodies’ eternal movements are not the exercises of capacities. Against this, I argue that these movements are the result of necessarily exercised capacities. I clarify what it is for a heavenly body to possess a nature and argue that a body’s nature cannot be a final cause unless the natural body possesses capacities that are exercised for (...) the sake of its nature qua form. This discussion yields a better understanding of what capacities are, what explanatory work capacities do, and what it is to possess a nature. (shrink)