Philosophical work[edit]
New essentialism[edit]
The new essentialism is a comprehensive philosophy of nature. Philosophers around the world, including Sydney Shoemaker, Charles Martin, George Molnar, George Bealer, John Bigelow, Caroline Lierse, Evan Fales, Crawford Elder, Nicholas Maxwell, Nancy Cartwright and John Heil, have contributed to in various ways to its development. The new essentialism is an emerging metaphysical perspective that is the culmination of many different attempts to arrive at a satisfactory post-Humean philosophy of nature.
However, this list of claimed allies has been disputed by Stephen Mumford, at least with regard to Shoemaker, Martin, Molnar, Heil and Cartwright.[5]
"Causal Powers and Categorical Properties"[edit]
In the chapter "Causal Powers and Categorical Properties" of The Metaphysics of Powers: Their Grounding and Their Manifestations, Ellis argues that categorical properties and causal powers are distinct from one another, and that categorical properties are not dispositional, but quiddities.[6] Quidditism accounts for identity of a property based only on what it is rather than what it disposes its bearer to do. Although categorical properties do not necessarily dispose their bearers to do anything, they do determine where active properties of things may exist, or be distributed, and thus where the effects of such activities can be observed.[6] He gives a detailed logical account of how a causal power can be defined. Ellis defines a causal power as a quantitative property that positions its bearer in specific circumstances to take part in a physical causal process with a certain outcome. Such powers are to either act or resist change within the bearer (e.g. temperature, elasticity).
All causal powers must meet two criteria. First, they must all have contingent locations, since they have to act from somewhere. Second, they all must have laws of action outlining their nature. Such laws reference both the location of the object that possesses the power, as well as the location of things it interacts with. Locations, however, are impotent. Ellis argues that neither locations nor categorical properties such as shape and size are causal powers, yet they can make a difference in outcomes.[6]