Define a time variable as full if it is of the form T = (t, t), where
(1) t is a variable whose values are mathematical objects (e.g. numbers)
(2) the value of t is the present of the reader of (2)
Both t and t are variables modelable in a mathematical theory, but their behavior with respect to the objects in the ontology of the theory are different.
I believe the use of full variables would clarify things in fundamental physics.
Similarly, define GREEN as full if it is of the form (green, green),
(3) green is a variable that ranges over knowledge about a particular shade of green
(4) green is a variable that ranges over █
Dualists claim fullness is non-trivial.