Since the 17th century, we’ve mostly viewed nature as a great machine whose workings we have to discover. We’ve also viewed God as the Chief Designer of that machine, wholly outside of nature and only interacting with it out of his own free will. But what Darwin did was show us that evolution can be explained by wholly natural processes that are to a large extent random and ‘by chance.’ No room for a designer there. No machine whose mathematical laws we can discover.
In short, Darwin eliminates the final vestiges of God (and therefore, any purpose nature might have) from our mechanical worldview. The only options are to either (1) cling to purpose in some small way like Intelligent Design people do; (2) reject Darwin altogether like Creation ‘Science’ people do; (3) reject God altogether like metaphyisical naturalists do; or (4) change our entire worldview.
Choice #4 is the toughest, but I’m convinced it is the only option with any hope of moving us forward.
Brent Henderson, in a comment on his own article titled Can Theology and Science Make Peace in the Age of Darwin?