Essentialism

Essentialists maintain that an object’s properties are not all on an equal footing: some are ‘essential’ to it and the rest only ‘accidental’. The hard part is to explain what ‘essential’ means.

The essential properties of a thing are the ones it needs to possess to be the thing it is. But this can be taken in several ways. Traditionally it was held that F is essential to x if and only if to be F is part of ‘what x is’, as elucidated in the definition of x. Since the 1950s, however, this definitional conception of essence has been losing ground to the modal conception: x is essentially F if and only if necessarily whatever is x has the property F; equivalently, x must be F to exist at all. A further approach conceives the essential properties of x as those which underlie and account for the bulk of its other properties. This entry emphasizes the modal conception of essentiality.

Acceptance of some form of the essential/accidental distinction appears to be implicit in the very practice of metaphysics. For what interests the metaphysician is not just any old feature of a thing, but the properties that make it the thing it is. The essential/accidental distinction helps in other words to demarcate the subject matter of metaphysics. But it also constitutes a part of that subject matter. If objects have certain of their properties in a specially fundamental way, then this is a phenomenon of great metaphysical significance.