According to these two blog posts, [1] and [2], the source is the film The Mindscape of Alan Moore. [3] I love the quote too, I just learned of it.
[1] http://dailyhumanist.wordpress.com/2011/05/24/the-world-is-r...
[2] http://pvewood.blogspot.fr/2012/04/some-alan-moore-quotation...