Full Idea
'Red' is surely not going to be opposed to 'Cayster' [name of a river], as abstract to concrete, merely because of discontinuity in geometrical shape?
Gist of Idea
We don't say 'red' is abstract, unlike a river, just because it has discontinuous shape
Source
Willard Quine (Identity, Ostension, and Hypostasis [1950], 2)
Book Reference
Quine,Willard: 'From a Logical Point of View' [Harper and Row 1963], p.69
A Reaction
I've been slow to grasp the truth of this. However, Quine assumes that 'red' is concrete because 'Cayster' is, but it is perfectly arguable that 'Cayster' is an abstraction, despite all that water.