It's a rare, but in my mind a kick a** position.
You see most Christian progressives (or liberals if you will) have what is called a "high anthropology" meaning that they think quite highly of human beings and what we are capable of all on our own. In other words, those with a high anthropology will perhaps say things like "all the truth you need to know is inside of yourself" or "we aren't bad sinful creatures, but are co-creators with God" to which I find myself thinking "what the hell planet are you from?, because here on Earth people just aren't that frickin' good...just read the paper or watch pretty much anything on the WB....we're NOT GOD...clearly.
As a good Lutheran I have what is called a "low anthropology". In other words I think that we are sinful depraved people in need of God's grace. Why do I believe this? Several reasons.
1) I know myself...pretty well
2) I take in the news
3) I have children. I didn't actually believe in original sin until I had kids, and I'm still not convinced, but now am sure that if humans are left unguided and undisciplined let me tell you...it ain't pretty.
4) I know other people
5) Did I mention that I know myself?...thoughts, words and deeds, what I have done and what I have left undone? Yeah, that's the best evidence. Slam dunk really.
Ok, so does that mean that I do evil shit all the time? No. Does it mean that I am some sort of demon child? Not most days. What it does mean is that the good in me and the good that I am able to do is as a result of God's always radical choice to use the broken and unlikely to do God's work in the world and not as a result of my own shiny soul. There is no true altruism, at least for me. I can't do a pure fucking thing to save my life. This is actually very hopeful. It means that there is a source from which I came and from which I draw and that source, unlike me, is endless. If my ability to "be good" is reliant only on my own goodness then I'm screwed. There is so much freedom in the fact that God and not myself is my source. However, to be a bit circular in my logic, I am still a broken person who inevitably will try and rely on self and not on God and will once again screw things up and be in need of God's grace which in always and already, just sittin' there waiting for me to realize it.
Still, I believe that we are made in the image of God and are Children of the Most High, but like all children we seldom know what's best for us and we need discipline.
As Luther said- we're a bit like snow covered dung - we look good but still smell like sh*t.