Full Idea
The law of excluded middle is ...the maxim of the definite understanding, which would fain avoid contradiction, but in doing so falls into it.
Gist of Idea
Excluded middle is the maxim of definite understanding, but just produces contradictions
Source
Georg W.F.Hegel (Logic (Encyclopedia I) [1817], p.172), quoted by Timothy Williamson - Vagueness 1.5
A Reaction
Not sure how this works, but he would say this, wouldn't he?
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.35