A groundswell of recent work in philosophy has sought to revitalize the analysis of causation by appealing to "active principles" such as powers, dispositions, capacities, tendencies, and propensities. These principles are described in a realist and rather Aristotelian fashion, in stark contrast to the deflationary and linguistic accounts of such principles characteristic of Humean thought and empiricist thinking more generally. Natures, essences, powers, and de re necessity are back in the analysis of causation. I do not argue in this paper for the plausibility of the revitalization project in general; instead, I explain how I think one aspect of it must be understood if the project is to be plausible. I suggest that those who are moved to resist Humean austerity and embrace a realism about things such as causal powers should take care in how they formulate this realism. Some Aristotelian notions, such as the concept of a causal power, may well be useful to modern studies of causation. Others, such as the notion that causal powers are determined by essences which comprise the natures of things, are outmoded in many sciences today. This paper focuses specifically on the notions of power and essence in the context of causation. Contra some of the most important recent proponents of the revitalization project, I contend that causal generalizations are not generally best understood as determined by the essential properties of natural kinds. How a member of a kind (natural or otherwise) behaves causally may be a function of its causal powers, but such powers need not constitute anything like the "essence" of a kind.
1. Revitalizing causation with dispositional essences
2. Causal behaviour in kinds without essences
3. Causal powers and inessential distributions