For reasons that aren’t entirely clear even to me, I started reading Friedrich Schleiermacher’s The Christian Faith recently. And the weird thing is, I’m really enjoying it. Schleiermacher is (in)famous as the “father of modern theology” or sometimes “the father of liberal theology”: he tried to re-establish Christian faith on a basis that took into account Enlightenment critics but also went beyond the narrow and sterile rationalist constraints that some Enlightenment thinkers tried to place on religion. Religion, according to Schleiermacher, is not based in thought (philosophy) or action (ethics), but a kind of experience, which he famously described as a “feeling of absolute dependence.” As I read him, this isn’t a purely subjective experience, but a clue to or an apprehension of an objectively existing relationship between the world and God, albeit one that we only become aware of in relation to ourselves. This experience is both the “datum” of religion and something which it is the goal of the religious life to cultivate.
This root religious experience, however, never comes to us “pure” so to speak. It always appears in a concrete form, which is conditioned by social, cultural, and historical factors, among other things. So, for Christians, the core religious experience is the experience of Jesus as our Redeemer. Everything in Christian theology flows from this. (This experience is always received within a “communion,” or church. Schleiermacher was no religious individualist.) According to Schleiermacher, Jesus possessed a perfect “God-consciousness”–which for him seems to mean something like an unwavering experience of this absolute dependence on the source of being. As Christians, we “catch” this God-consciousness from Jesus by being part of the church, and gradually we come to share in it more and more fully. (I’ve only just finished the–128 page!–introduction to The Christian Faith, so a lot of the details haven’t been worked out yet. But I think this is the general gist.)
One interesting thing that falls out of this account of the “essence” of Christianity is that Schleiermacher is able to explain what he calls the four “natural heresies” that tend to arise throughout Christian history. If the core of Christian experience is that of Jesus as our Redeemer, then this implies that (1) we are in need of redemption, (2) we can be redeemed, (3) Jesus is sufficiently unlike us that he can be our Redeemer, and (4) Jesus is sufficiently like us that he can be our Redeemer. So, according to Schleiermacher, your four modal heresies are those that deny one of these four propositions:
–“Pelagianism”–we don’t need redemption as such, though we may need someone who can show us how to be a little better.
–“Manicheism”–creation is so corrupted/wicked that it is essentially irredeemable.
–“Nazaritism” or “Ebionitism”–Jesus is just a human like us, so does not posses any special quality that can redeem us.
–“Docetism”–Jesus only appeared to be fully human, and so is too unlike us to provide the kind of redemption we need.
Schleiermacher is careful to point out that these are idealized types, and may not be perfectly instantiated in history. But he thinks that identifying them can help further clarify what the essence of Christianity consists in. In any event, I found the discussion enlightening.
A Thinking Reed 
“Thomas Aquinas and Immanuel Kant made some particular judgments about sex that nearly all of us (conservative and liberal) would now reject.”
I would be interested in knowing just exactly which judgments made by Thomas Aquinas about sex would be rejected by nearly all of us conservatives.