Full Idea
Frege's quantificational logic vindicates Kant's insight that existence is not a predicate and leads to fallacies when treated as one; and we might also say, despite Hegel, that there is no concept of being.
Clarification
Frege's quantifiers are 'for all x' and 'there exists an x'
Gist of Idea
Frege's logic showed that there is no concept of being
Source
report of Gottlob Frege (works [1890]) by Roger Scruton - Short History of Modern Philosophy Ch.17
Book Reference
Scruton,Roger: 'A Short History of Modern Philosophy' [ARK 1985], p.246
A Reaction
I notice that Colin McGinn has questioned the value of quantificational logic. It is difficult to assert that 'there is no concept of x', if several people have written large books about it.