Full Idea
Rejecting the standard views that essences are individuated by either actual existence, quantity or matter, Scotus said that the principle of individuation is a further substantial difference added to the species - the so-called haecceitas or 'thisness'.
Gist of Idea
Scotus said a substantial principle of individuation [haecceitas] was needed for an essence
Source
report of John Duns Scotus (works [1301]) by Stephen D. Dumont - Duns Scotus p.206
Book Reference
'Shorter Routledge Encyclopaedia of Philosophy', ed/tr. Craig,Edward [Routledge 2005], p.206
A Reaction
[Scotus seldom referred to 'haecceitas'] I suppose essences have prior existence, but are too generic, so something must fix an essence as pertaining to this particular object. Is the haecceitas part of the essence, or of the particular?
Related Idea
Idea 22126 Avicenna and Duns Scotus say essences have independent and prior existence [Duns Scotus, by Dumont]