A Dualist Metaphysics of Nature

I start this chapter with a presentation and critique of Brian Ellis’ new essentialism, which consists in a dualist metaphysics of laws based on both categorical properties and powers. Like Ellis, I defend a dualist metaphysics of nature. However, unlike him, I attempt to dispense with essences and natural kinds and advocate an enlarged view of categorical properties. These include not only spatial and structural properties but all observable properties. Besides, I submit that categorical properties are not quiddities and that their identity across possible worlds doesnot reduce to a mysterious primitiveness. I also develop an empirical argumentation in favour of the reality of irreducible causal powers which ground the necessity of laws and their associated counterfactual conditionals. Since the instantiation of powers is relative to some possible worlds, the necessity of laws of nature is contingent. Such conditioned de re necessity of laws is distinct from the de dicto necessity of analytic propositions.