Puzzle--how to get around these apparent dependencies of the modern synthesis on supernatural powers?
Natural selection works by whittling down the number of less-fit variations. As fast as it does so some agency must add new variations, otherwise natural selection would run out of variations to select from and evolution would cease. Failure to find a non-supernatural agency able to account for the creation of new variation led to natural selection being almost abandoned after Darwin's death.
But did the addition of genetic mutation help? Genetic mutation by itself leads to harmful mutations that, accumulating generation by generation, would lead to rapid extinction. Natural selection's effect, being so slight, can do little to slow that accumulation. But according to population statistics, when that slight effect acts in favor of beneficial mutations it can increase their incidence to make them the dominant form of their gene, although that would take millions of generations. For that time to be availalble something must be suppressing the accumulation of the harmful mutations that would otherwise lead to extinction in just a few generations. That can only be supernatural powers in the beneficial mutation.
Illustration: Take two species competing in the same niche. Both suffer genetic mutation but the second one has a perfect repair mechanism so no mutations survive into its phenotype. Until beneficial genes appear in the first species it accumulates harmful genes and extinction threatens. But once a beneficial gene appears, all that accumulation of harmful genes must supernaturally disappear and only beneficial mutations will increase in incidence, leading after millions of generations to eventual evolution and dominance in the niche. Without this supernatural power of the beneficial mutation, how else how can one account for mutations helping species evolve?