ABSTRACT
Modality' is the name given by contemporary philosophers and logicians to the study of possibility and necessity. A modal claim is any claim which contains words such as 'possibly', 'necessarily' and cognate expressions such as 'essential', 'accidental', 'might', 'must', 'could', 'would', etc. The distinction between essential and accidental properties derives, like so much in metaphysics, from Aristotle. The idea is that some properties of an object or natural kind are essential, others accidental. So it may be that Socrates is essentially human but accidentally bald, or that tigers are essentially animals but accidentally striped. W. V. O. Quine thought Aristotelian essentialism incoherent and held that whether an object has a property essentially or not depends on how that object is named or described. Essentialism is the metaphysical view, originating in Aristotle, that objects and natural kinds have some properties essentially and others accidentally.
