Human Agency, Realism and the New Essentialism

Abstract

The new essentialism¹ is a metaphysic for a species of scientific realism that embraces the theoretical entities of most of the accepted causal process theories of science, as well as the causal powers, capacities and propensities of the things that are necessarily involved in these processes. Let us call those who are realists about all such entities ‘causal process realists’. It has been argued elsewhere (Ellis 2001, and forthcoming) that the new essentialism provides a sound basis for such a realist ontology. It entails that there are hierarchies of facts about the world that exist independently of anyone’s knowledge or understanding. It explains the modal structure of the world, with its natural necessities, and its hierarchical system of laws of nature. It may not be necessary to accept the whole metaphysical stance of the new essentialism to be a causal process realist. For the ontology would appear to be defensible, even if one does not accept all of these metaphysical explanations. But, as Stathis Psillos (1999) has argued convincingly, a scientific realist must at least accept that the world has a natural kinds structure, and this is already a first step in the direction of essentialism.