Keeping Body and Soul Together: The Z.3 Puzzle and the Unity of Substances

Aristotle\u27s Metaphysics is a tract concerned with being, and the central books focus on those entities which most unqualifiedly partake in being: substances. Book Z, in particular, is devoted to the articulation of criteria by which to distinguish substances from non-substances, to the identification of substances, and to an examination both of the relationship between substances and their properties and of that between form and matter. This last topic is particularly pressing for Aristotle, for having supplemented the doctrine of the Categories with a hylomorphic analysis of substance he must now determine whether and how form and matter can combine to produce a truly unified substance. There is a temptation to assimilate the relationship of form and matter to that of substance and accident, a temptation which must be laid at Aristotle\u27s own doorstep. The examples he commonly uses to illustrate the notions of form and matter, examples such as the bronze and the shape of a bronze sphere, suggest that the form as such has no intimate relation to the matter as such. But in the Metaphysics he finds that considering the relationship of matter and form always to be that of accidental predication has disastrous consequences, so he must struggle to find a new model for their inter-relationship. The first moment of this struggle will be the subject of this essay: the famous stripping argument of Z.3. I shall contend that this passage contains a premise, often overlooked in discussions, which identifies the argument as non-Aristotelean and whose denial provides Aristotle with a means of avoiding a paradox. In order to explain why this premise is unacceptable, he must introduce the notions of energeia (actuality) and dunamis (potentiality), using them to explicate the connection between substantial form and matter. But in order to see how he arrives at this point, let us begin with our passage

On the Status of Conservation Laws in Physics: Implications for Semiclassical Gravity

We start by surveying the history of the idea of a fundamental conservation law and briefly examine the role conservation laws play in different classical contexts. In such contexts we find conservation laws to be useful, but often not essential. Next we consider the quantum setting, where the conceptual problems of the standard formalism obstruct a rigorous analysis of the issue. We then analyze the fate of energy conservation within the various viable paths to address such conceptual problems; in all cases we find no satisfactory way to define a (useful) notion of energy that is generically conserved. Finally, we focus on the implications of this for the semiclassical gravity program and conclude that Einstein's equations cannot be said to always hold

The Message of the Quantum?

We criticize speculations to the effect that quantum mechanics is fundamentally about information. We do this by pointing out how unfounded such speculations in fact are. Our analysis focuses on the dubious claims of this kind recently made by Anton Zeilinger