Historians of science often point out bits and pieces of philosophy from the ancient world that were possibly ancestral to modern science. It is not hard to find ancient philosophers who believed in an ancient world that has changed over time, which is a rudimentary form of evolution. But perhaps Darwin’s main contribution to science, and one that took a lot of his fellow scholars by surprise, was natural selection. As Daniel Dennett has pointed out in Darwin’s Dangerous Idea, natural selection brings the world of chance and the world of order together into perhaps the most powerful idea that has emerged in the history of human thought. For those of you who do not know what natural selection is, it occurs when replicators (such as organisms or ideas) have heritable diversity, and then some of them replicate more than others.
I ran across one possible precursor of the idea of natural selection in De Rerum Natura by the Roman philosopher Lucretius. His view of the universe most closely resembled that of the atomists, although he did not use this term. He believed that these atoms, or elements, or particles came together to form everything that we see in the world. But there was no divine hand assembling them together into the right or the best forms. Instead, they came together at random. Some of these random assemblages worked better than others. This would, in fact, be an ancient statement of natural selection. Lucretius did not say it quite this clearly, but…see what you think. Lines 1025-1031 of Book One of De Rerum Natura reads, referring to atoms, “…but in numbers vast, shifting now here, now there, throughout the whole, harried by blows relentless down the course of endless time, trying now this now that of motion and of union, they at last come into patterns such as those whereby this world of ours is built…” In Book Two, Lucretius says that because atoms came together to form great things in our world, they might also have done so in other worlds, and done so differently. Whether this is just a Star Trek view or a multiverse view, I cannot say, but it is an example of a rudimentary form of this idea almost two thousand years before Darwin made it explicit.
I am nearly certain that Lucretius’ ideas had little influence on the development of science. His manuscript was almost literally an example of the cliché of the last copy being saved from the kindling pile. But the strength of the idea may be illustrated by the fact that it occurred independently in more than one great mind.