Abstract

The term 'essentialism' in its popular usage is usually qualified in some way, as in 'biological essentialism', 'gender essentialism' and 'social essentialism'. The essentialist theses were defended on the grounds that denying them leads, under plausible assumptions, to pairs of worlds containing objects which are intrinsic and spatio‐temporal duplicates and yet which are numerically distinct. This chapter outlines some technical difficulties in getting the definitions of 'essential property' and 'individual essence' exactly right. It explains the idea of a metaphysically essential property in terms of Aristotle's 'essential/accidental' contrast. A popular idea is to invoke the notion, which has its roots in Aristotle's theory of essence and accident, of a substance sortal. A different way of developing a sortal‐based account of essential kinds is suggested by David Wiggins, who argues that it is only ultimate sortals that represent essential properties, where an ultimate sortal is the most general sortal corresponding to a given principle of individuation.