Full Idea
I think the validity of the 'Law' of Excluded Middle depends on the assumption that every proposition is definitely true or definitely false.
Gist of Idea
The 'Law' of Excluded Middle needs all propositions to be definitely true or definitely false
Source
Peter van Inwagen (Material Beings [1990], 18)
Book Reference
Inwagen,Peter van: 'Material Beings' [Cornell 1995], p.262
A Reaction
I think this is confused. He cites vagueness as the problem, but that is a problem for Bivalence. If excluded middle is read as 'true or not-true', that leaves the meaning of 'not-true' open, and never mentions the bivalent 'false'.
Related Idea
Idea 9024 Excluded middle has three different definitions [Quine]