Essence, Existence, and Modal Knowledge

Abstract

AbstractThis chapter considers some typical cases of metaphysical necessity. First, it is argued that nothing exists metaphysically necessarily, and so everything exists contingently. This requires a comment on the Barcan Formulas: it is argued that we should reject the Barcan Formulas for logical, and hence for metaphysical, modality, by rejecting an existence assumption in classical logic. The chapter then considers the extent to which essentialist necessity claims, such as the essentiality of kind, can be accommodated by the account of metaphysical necessity. It is proposed that essentialist claims may be accommodated as claims of generalized identity. The chapter also addresses some epistemological issues. Metaphysical necessity is often associated with the necessary a posteriori. The chapter explains where a posteriori knowledge might figure in knowledge of conditional metaphysical necessities, using the template of deduction models of modal knowledge. It is further suggested that the distinction between thinking and objective thinking can help to shed light on the notion of conceivability as a guide to possibility. We may distinguish between conceivability understood in terms of what is thinkable, and conceivability understood in terms of what is objectively thinkable. Logic helps us to explore the first kind; transcendental philosophy helps us to explore the second.