No, we don’t know why, but neither does this person. Not short of an opinion about Uncommon Descent, though:
In typical fashion, Uncommon Descent are hoping for the worst: The “Darwinism” killed his faith. (Must. Control. Rage. Must not stoop to their level…) Let’s hope their just being despicable and there’s nothing to their speculation other than malice. Giberson is a good man and we need him in this fight.
Hard to say why “public theology” student Arni Zachariassen, who is supposed to favour “Thoughtful Theological Reflection” (blog’s title), should be in a barely controlled rage. Did Uncommon Descenters say that Darwinism had killed Giberson’s faith? The consensus here is that he was “a bridge too far” for – that is, not a good fit with – the BioLogos organization.
(Note: – AZ has since clarified his position. See this comment.)
Put another way: Giberson was way better for us than for them.
That may not, of course, be why he left (we still don’t know). But here’s conventional UD-type thinking: First, what exactly is BioLogos’ mission anyway? Surely not to front liberal theology as such; whole denominations now exist to empty churches and synagogues by doing that. The mission is to persuade orthodox Christians to put aside growing doubt and wholeheartedly embrace Darwinism and all it entails.
Now, the worst way to go about that is Giberson’s: Point blank make clear that treasured lifetime beliefs must be dumped. Faced with that, the orthodox Christian sticks to his beliefs and dumps BioLogos. So?
Francis Collins, who had no choice but to resign from Biologos in order to accept his appointment as National Institutes of Health head, had a much better strategy: Clouds of clouds, sentimental evocations of CS Lewis, folksy guitar strumming, more clouds for more crowds.
They must want him back as soon as he retires.