Over at the Uncommon Descent blog, there is quite a good discussion going on around a paper published by two Finnish scientists about whether evolution is directed or not. Scroll down in the comments to read some interesting discussions about natural selection.
Darwin said:“Several writers have misapprehended or objected to the term Natural Selection… [Natural selection] implies only the preservation of such variations as arise and are beneficial to the being under its conditions of life… It has been said that I speak of natural selection as an active power or Deity; but who objects to an author speaking of the attraction of gravity as ruling the movements of the planets? Every one knows what is meant and is implied by such metaphorical expressions; and they are almost necessary for brevity. So again it is difficult to avoid personifying the word Nature; but I mean by nature, only the aggregate action and product of many natural laws, and by laws the sequence of events as ascertained by us.”
Darwin here conflates two things, natural laws, and the human descriptions of those laws. Natural laws exist independently of human description. Whether humans had described the laws of gravity or not, it existed. He then proceeds to assert that natural selection falls in that category. There is no non-circular proof that natural selection is indeed as axiomatic as gravity. For that to hold true, natural selection must be self-evidently true, in all cases, everywhere. As we have seen with the breakdown of physical laws at the quantum level, that is not even true for gravity.
One of the commenters there rightly asks the question:”What is natural selection a cause of?” The circularity of natural selection has long been proposed by opponents of evolution, and denied by its supporters.
Natural selection boils down to fitness of organisms and the survivability of those organisms in specific environments. The selection is the preservation of those organisms best suited to survive, and therefore reproduce more, ensuring that, over time, those organisms outlive those that are not quite as adapted to survive.
Not quite as simple, though. Firstly, the circularity is apparent. Natural selection selects that which is most fit to survive. Which are most fit to survive? That which is selected.
Secondly, Lewontin (2003), points out
“In modern evolutionary theory, however, “fitness” is no longer a characterization of the relation of the organism to the environment that leads to reproductive consequences, but is meant to be a quantitative expression of the differential reproductive schedules themselves.”
So is selection natural or guided? Is it random or by script? If the reproductive differentials are quantified, as Lewontin pioints out, then how do they claim non-random randomness? Or is it guided by “Nature”, the metaphorical force that Darwin made literal? Isn’t it totally superfluous?
For the atheistic philosophers, it takes the place of a guide, and does away with the need for any underlying intelligence in the universe, and therefore they will continue to play dumb on the inherent flaws of natural selection. It is their prior religious commitment, not rational thought, that selects natural selection for survival.