Does 'redness' exist, or just red things?

Two apples are both red — but does 'redness' itself exist as a real thing they both share, or is it just a name we apply to similar objects? Plato said such universal properties exist independently and eternally; Aristotle said they exist only inside particular things; centuries later William of Ockham argued they don't exist at all outside the words we use for them. The disagreement has run from ancient Athens through medieval scholasticism into modern philosophy of language.

— Wikipedia contributors, Problem of universals — Debate spanning Plato, Aristotle, Boethius, Abelard, Ockham