ABSTRACT
This chapter presents one representative contemporary account and one representative medieval account of emergence and causal powers. It explores the difference between these two positions and the implications of that difference for accounts of emergence. The chapter considers briefly one account of emergence weaker than that defended by O'Connor and Churchill (O&C), namely, that argued for by Mark Bedau. It shows that, contrary to what one might initially suppose, it differs in substantial ways from Aquinas's account as well. The medieval account illuminates a position that has not yet been sufficiently explored in the contemporary discussion but that is worth taking seriously as regards emergence. The chapter briefly summarizes Aquinas's Aristotelian account of substantial forms, for the sake of considering the way in which it is and is not like the account of emergent properties O&C give. There are other accounts of emergence besides that offered by O&C, and some of them are weaker than that argued for by O&C.
