Pulitzer Prize–winning author Marilynne Robinson captures well a dilemma that occurs within Darwinism:
Surely we must assume that a biosphere generated out of any circumstances able to sustain life is as good as any other, that if we make a desert, for example, and the god of survival turns his countenance upon the lurkers and scuttlers who emerge as fittest, under the new regime, we can have no grounds for saying that things have changed for the worse or for the better, in Darwinist terms. In other words, absent teleology, there are no grounds for saying that survival means anything more or other than survival. Darwinists praise complexity and variety as consequences of evolution, though the success of single-celled animals would seem to raise questions. I am sure we all admire ostriches, but to call a Darwinist creation good because it is credited with providing them is simply another version of the old argument from design, proving in this use of it not the existence of God but the appropriateness of making a judgment of value: that natural selection, whose existence is to be assumed, is splendid and beneficent, and therefore to be embraced.
The Death of Adam: Essays on Modern Thought [1], “Darwinism,” p.44
It doesn’t prove theism (or creationism, for that matter), but the Darwinist inability to adequately explain why something is or isn’t good would itself seem to undermine its usefulness as an explanation for the natural world.
Sure, a Darwinist might argue that they’re only performing empirical analysts of what things are — not the why. But I submit that we can’t truly know the what without knowing the why.