The
battle cry of
Soren Kierkegaard's final set of articles and pamphlets, which held that
Christianity was a radical challenge to the social order and that the "Christianity" of his day (the
19th century) was socially acceptable and therefore not really Christianity, but
Christendom.
The conclusion "Christianity does not exist" is also the reductio ad absurdum of a common dodge among Christians who explain that aspects of Christianity they don't like are not really Christian. Since everything Christians do has been labelled as un-Christian by one Christian group or another, we might conclude that Christianity does not exist.