One might, with Darwin, theorize that the development of the biosphere was simply down to that empirically unattested variant of chance, “natural selection.”
The classical pantheon, lacking moral credibility, had become a source of embarrassment to thoughtful Greeks.
What distinguished thinkers had long called out for its manifest absurdity was now, Phoenix-like, rising from the ashes.
Darwinism, when viewed from a philosophical perspective, might more accurately be understood as a late sub-branch of ancient speculative thought.
Bottom line: Darwin did not have a single scrap of empirical fieldwork to document his conjectures.