I argue that supervenience is an inadequate device for representing relations between different levels of phenomena. I then provide six criteria that emergent phenomena seem to satisfy. Using examples drawn from macroscopic physics, I suggest that such emergent features may well be quite common in the physical realm.

Diachronic emergence has recently been characterised as transformation. This aims to capture the thought that the entities that emerge are radically new or different. Transformation is hence closely linked with a central (but rarely raised) challenge for all emergentists: how to account for the identity and individuation of entities involved in emergence. With this challenge in view, I develop and probe four interpretations of transformation: addition, replacement, fusion, and transubstantiation. Of those, transubstantiation provides the most plausible response to the challenge (...) about identity. Accordingly, diachronic emergence is a transformative process whereby an individual passes from one primary kind to another. (shrink)

Our cognitive capabilities force us into a description of the world by levels. But theories on different levels result in descriptions that differ qualitatively. Therefore, the resulting incommensurability requires ontological bridges between such theories. These are obtained uniquely when the equations of the reduced theory are compared with a suitable limit of the equations of the reducing theory. Four case studies from theoretical physics and astronomy support this claim, two for theories of composites and two for non-composites (field theories). These (...) results a coherent view of a single real world despite its ontological pluralism. The cumulativity of scientific knowledge is thus ensured and realism is supported. (shrink)