I just finished reading the section in Velvet Elvis about the Brick Walls and Trampolines, which Terry referred to in this post.
Here are my thoughts:
Lets not discredit Rob Bell for using the virgin birth as his example for the brick analogy. He openly states on the very next page, "I affirm the historic Christian faith, which includes the virgin birth and the Trinity and the inspiration of the Bible and much more."
But the meat of the matter is his analogy of the brick wall and the trampoline. For those of you who have not read this section, the analogy is two parts.
Brick Wall: He is observing that many Christians' faith is brick-like. In other words, one belief is a brick, and each brick sits on top of another brick.
My take: In many ways, this analogy rings true. How else would we have so many different denominations? I think of it as a Lego brick wall. Presbyterians and Protestants might have very similar walls, with a few different colored bricks in the top, middle, and bottom. Some denominations' walls will have different shapes and colors than other walls, but hopefully most of the bottom bricks are the same. We can maybe even say that some of the bottom bricks are different shades of the same color.
Bell goes on to note that "walls" are often defended, and aren't necessarily encouraging for growth, but are more often used as boundaries. I think his analogy breaks down here. First of all, bricks work great if you are describing foundational truths, and how some truths are based on the truth of others. Bricks can also be used to build structures or shelter. Walls shouldn't be the first connotation when we think of bricks. I'm sure that there are many walls Christianity (the Christianity as humans have made it) has built, some good, some bad, some as shelter, but they are not all bad walls. Also, he is only describing the analogy when he says that the virgin birth is only a brick, and what would happen if it was removed? I tend to believe that the virgin birth is a bottom brick, but not the bottom. Christ is the cornerstone after all. If the virgin birth was removed, Christ would still stand and so would a lot of other bricks. (Notice the contrast from this post and my previous post, I still haven't figured it out, and probably never will. God is beyond my comprehension and I like him like that). But let it be said that I think the virgin birth is immovable, because it is so clearly stated in a book I believe is truth.
Trampoline: Here Bell is describing how some aspects of our faith serve as springs in trampolines. They help us understand things better and help us jump higher. Just like jumping simultaneously on a trampoline you can get a much higher "bounce" if you time your jump just right with your partner's landing. One example of a spring is the Trinity. The word trinity is not explicitly stated in scripture. But when we use that "spring" it brings to light so many other aspects of God that we would have had a harder time understanding otherwise. Bell states that springs are not what make up Christianity, but are what help us understand it better.
My take: The trampoline idea is great, but as with most ideas, could be potentially dangerous. Purposefully looking for new springs without discernment can result in a higher jump, but some of them could eventually jump you off the trampoline entirely. I realize I am further stretching this analogy to relate it to getting off course but I feel justified in doing so in light of Bell's stretching of the brick analogy into forming walls.
I also think that while something may be a "spring", it wasn't given to us by our constant thinking and questioning. A true spring is revealed to us by God. God may reveal it to us through our study of scripture, but it is definitely not a man-made revelation. Any not God given spring is definitely one that flings us off the trampoline no matter how subtle it may do so.