Full Idea
If we treat disjunction in the standard way and take the negation of a statement A to mean that A is false, accepting excluded middle forces us also to accept the principle of bivalence, which is the dictum that every statement is either true or false.
Gist of Idea
Standard disjunction and negation force us to accept the principle of bivalence
Source
Edwin D. Mares (Negation [2014], 1)
Book Reference
'Bloomsbury Companion to Philosophical Logic', ed/tr. Horsten,L/Pettigrew,R [Bloomsbury 2014], p.181
A Reaction
Mates's point is to show that passively taking the normal account of negation for granted has important implications.