Once the idea of evolution clicks, it's hard to stop applying it. Not just to organisms, but to molecules, to brains, to ideas, to whole cultures and technologies. And once you line them up, they seem to stack: ideas and culture sit at the top, with the broadest control over everything beneath them. The evolution of our culture now shapes the fate of every other living thing on the planet far more than genes do.
Science, in this light, isn't a body of facts so much as a framework for evolving ideas — complete with an immune system. Scientists generate a sea of ideas (memes), and most get thrown out, pruning the tree the way a developing brain prunes the connections it doesn't use. The selection rules are simple: an idea has to be testable, ideas that fail their tests are discarded, and among the survivors the ones that make the widest set of exact predictions win. You want maximum diversity of ideas going in, and ruthless, fast pruning coming out.
I try not to take the reductionism too far. It's tempting to say the evolution of ideas just is the evolution of molecules a few levels up, but that flattens something real. Ray Kurzweil put the romantic version of it well:
Evolution moves toward greater complexity, greater elegance, greater knowledge, greater intelligence, greater beauty, greater creativity… And God has been called all of these things, only without any limitation. Thus the freeing of our thinking from the severe limitations of its biological form may be regarded as an essential spiritual quest. — Ray Kurzweil
Whether or not you go that far, the throughline is hard to unsee: it's evolution all the way up.