Darwin, in his explanation for his theory, discussed a number of characteristics of life and reproduction that were all but impossible to contest. For instance, he discussed the apparent passing of traits from parent to progeny. It was undeniable, he said, that superficial characteristics that appear on one or both parents would be transferred to some degree to the offspring. If it could be agreed, even by his critics and deniers, that this was the case, then it must also be true that other underlying variations would be passed on. The important point here, is that some of those changes would be beneficial, and some not. Those that were beneficial would proliferate, and allow for still more changes. I found Darwin’s conclusion to his theory to be quite entertaining. I got the impression that he enjoyed discussing (dismantling) the counterpoints offered by his critics. The “blindness of preconceived opinion”, as he called it, was the foundation for the vast majority of his critics claims. Those critics demand the most intense scrutiny from Darwin’s theories because they felt his ideas went against the established “truth”, the certainty of which had been completely taken for granted. And at every turn, a logical and testable answer was put forth in response. But when the same rigorous questioning was applied to their established ideas, the attitude was changed and the answers were not forthcoming. They feel that if it is not known, it does not need to be known and that to search for answers in creation would be disrespectful to the creator.
The one claim for the stability of his theory that I found to be most interesting was the comparative nature of “mainland” species and “island” species. Those species found on a coastal island will very closely match those of the immediately adjacent mainland, and one can find, in an old enough system, very slight variations between counterpart species. It is fascinating to me to consider the possibility of actually seeing speciation as it happens (only a snapshot over vast timescales obviously) simply through migrating to a remote region. One of my personal favorite examples of this phenomenon is the Tepuis of central South America. These plateaus are completely isolated from the surrounding lowlands and feature a variety of species that are endemic only to the top of the plateau and can not be found anywhere else on Earth.