It occurred to me as I mulled Stanley Fish's review of a symposium of Jurgen Habermas on religion in public life that one way to explain why I find Habermas' approach so misguided would be to relate my own almost-finished reading of Susanna Clarke's marvelous novel Jonathan Strange & Mr. Norrell. Two magicians appear to revive English magic. It is the desire of the first to steer clear of anything having to do with Fairies, Faerie, or the mysterious medieval king of northern England, John Uskglass, known as the Raven King. Yet, in pursuit of his quest for reviving English magic, Mr. Norrell, of Hurtfew Abby, Yorkshire, bargains with a Fairy, trading the life and sanity of a woman for the goal of establishing magic.
The end result of the struggle to establish magic upon sound, rational principles, purged of what Norrell considers "mysticism", is the realization that that which Norrell claims to despise the most - the Raven King, Fairies, the "mystical" notiont that England is as much founded upon magic as upon anything - is at the very heart of his attempted project. Strange understands this all too well, and he pays dearly as well, but is willing to bear the cost (although he does free Lady Pole and others from their enchantment at the hands of the Fairy).
The gist of this review is simple: the attempt to make something "rational", by some random definition, of a pursuit that at its heart is not wholly rational is doomed to failure. Habermas' attempt to lasso religion in service of some greater social good - what I called an Erastian bargain - works well enough where it is employed as some kind of official doctrine of a state. As a way of understanding the heart of the Gospel message, however, it is doomed to failure. The message of the Church - the Good News of God's prodigal love for all creation - cannot know any limit or boundary. In Herbert Marcuse's definition, it is indeed a totalitarian ideology; that is to say, there can be no aspect of one's life or thought that it does not penetrate. This is not a criticism of it, by any means.
Setting artificial, arbitrary boundaries to the expression of religious belief - no fundamentalism! no metaphysical nonsense! - strips Christianity of its very heart. While it may work as a social ameliorative (Habermas' decision to use a funeral as an example is a marvelous instance of this way of thinking), it makes of religious belief something other than "Christian".