An epistemic distinction among essences, its metaphysical ground, and the role of philosophy

Abstract Uniformism is the view that one and the same epistemology should apply for all modal knowledge. I argue that, whether or not all modal knowledge can be accounted for in terms of knowledge of essences, uniformism about knowledge of essences is untenable. I do this by showing that, while some essences are empirically discoverable, others are not. I then argue that the uniquely realisable–non-uniquely realisable distinction is a better metaphysical candidate for grounding this epistemic difference than the concrete–abstract distinction. I conclude by suggesting that the task of philosophy is to identify non-empirically discoverable essences.