Where’s the white hot furnace that powers evolution? For Darwin it lay in natural selection pitting the members of a species against challenges from the environment, those members carrying the more favorable variations emerging as heroes, qualified to breed, less favorable variations along with the creatures carrying them getting swept away as dross.
The “Modern Synthesis” relocated the furnace to the forge generating the genetic mutations that supposedly presented to natural selection the variations it needed to operate on.
These notions, natural selection and genetic mutation, are biology’s equivalent of quantum mechanics. They’re non-intuitive, and get presented to us in the form of abstruse mathematics that ordinary people are guaranteed not to understand. Common to both is rejection of how nature looked to people when they first wondered what made living creatures evolve. What seemed obvious to those observers was, evolution came from variation. As variation accumulates, as new combinations of variations favor new lifestyles, species split in two. Species originate through there always being new variations encouraging creatures to adapt to the environment in new ways.
We may need to go back to that old notion of evolution being driven by variation. First, it seems Darwin was wrong. After millennia of evolution, living creatures display much more variation than you’d expect if natural selection had all that time been burning away all except a single optimal set of variations. Take the wolf, for example. Think how many breeds of dog originally came packaged as variation in the wolf. If all but the most favorable variations had been continually trimmed away by natural selection, some other process must have all that time, just as rapidly, been generating new variations, variations good enough for making dogs. But breeds of dogs breed true, new variations seldom showing up. So variations aren’t continually being generated, they’re rare. The variation found in the wolf must have built up slowly over time, undisturbed by natural selection.
Second, if natural selection is not what drives evolution, then random genetic mutation can’t be the source of variation—the majority of mutations are harmful; without something to burn away all that dross a species would quickly go extinct. Variation seems to come all ready to meet the challenges of the environment without any selection being necessary.
A theory like that makes accounting for evolution childishly simple. How did humans evolve? First, by the addition to an existing ape of variations for greater manual dexterity, capacity for speech, upright posture, greater intelligence, and so on; then by creatures carrying those variations separating out to become a new species.
This is a good news/bad news theory of evolution. The good news is, this is how nature actually looks; it seems to come with abundant variation, ready for use. As it accumulates, lifestyles diverge and species separate out. And that’s why living creatures appear so spectacular—they’re the embodiment of eons of the creation of new variation.
The bad news is, if evolution consists of only the creation of new variation, and no selection, then variations must come as improvements ready to use, and that seems to amount to intelligent design. Whether or not that’s a problem depends on how you feel about intelligent design. Apart from that, though, locating the white hot furnace that drives evolution in whatever process generates variation seems a good idea.