Full Idea
The lack of a proper identity concept for attributes (properties) is a lack that philosophers feel impelled to supply; for, what sense is there in saying there are attributes when there is no sense in saying when there is one attribute and when two?
Gist of Idea
There is no proper identity concept for properties, and it is hard to distinguish one from two
Source
Willard Quine (Speaking of Objects [1960], IV)
Book Reference
Quine,Willard: 'Ontological Relativity and Other Essays' [Columbia 1969], p.19
A Reaction
This strikes me as being a really crucial question. There is a mistaken tendency to take any possible linguistic predicate as implying a natural property. I sympathise with the sceptics here (see Ideas 4029, 3906, 3322). How to individuate properties?
Related Ideas
Idea 4029 Nominalists ask why we should postulate properties at all [Mellor/Oliver]
Idea 3906 If possible worlds are needed to define properties, maybe we should abandon properties [Scruton]
Idea 3322 Quine says that if second-order logic is to quantify over properties, that can be done in first-order predicate logic [Quine, by Benardete,JA]
Idea 23227 Each object has a precise number of properties, each to a precise degree [Fichte]