And then what?" said her Dæmon sleepily "build what?" "The Republic of Heaven. - Philip Pullman

"one thing that I realized early on in thinking about this book, when I found, to my consternation, that I was writing a fantasy. I hadn't expected ever to write a fantasy, because I am not a great fantasy fan. But I realized that I could use the apparatus of fantasy to say things that I thought were true. Which was exactly what, I then realized, Milton had been doing with Paradise Lost. Paradise Lost is not a story of people and some other people who've got wings. It's not one of those banal fantasies that just rely on somebody having magic and someone dropping a ring down a volcano. Paradise Lost is a great psychological novel that happens to be cast in the form of a fantasy, because the devils and the angels are, of course, embodiments of psychological states. The portrait of Satan, especially in the Temptation scene (I think it's in Book 9), is a magnificent piece of psychological storytelling.

So it was possible to do, I realized, and with Milton as my encouragement, I launched into this book — which I reluctantly accept has to be called a fantasy. Finding physical embodiments for things that were not themselves physical was one of the ways I approached what I wanted to say. But then, that's what we do with metaphor all the time. That's the way metaphor works. The way metaphor works is not the way allegory works. Allegory works because the author says, "This means so-and-so, that means such-and-such, and this can only be understood in such-and-such a way. If you don't understand it like this, the book won't work."

It seems to me that some critics of mine, from the religious point of view, are treating my novel as if it were an allegory and they had the key to it. It is not an allegory, and they don't have the key to it, because there is no key apart from the sympathetic and open-minded understanding of the reader."

Her last conscious thought was disgust at life; her senses had lied to her. The world was not made of energy and delight but of foulness, betrayal, and lassitude. Living was hateful, and death was no better, and from end to end of the universe this was the first and last and only truth.

As for what it's against - the story is against those who pervert and misuse religion, or any other kind of doctrine with a holy book and a priesthood and an apparatus of power that wields unchallengeable authority, in order to dominate and suppress human freedoms.