by alecto » November 1st, 2006, 4:41 am
Biologists don't seem to use the terms "Darwinism" and "neo-Darwinism" much. "Evolution" encompasses a broad spectrum of ideas, some of which have explanitory value and some of which also have had predictive value. "Neo-Darwinism" is supposed to mean Darwin's theory with the two major difficulties resolved: where the hereditary information is stored (genes) and that there are mechanisms of mutation of genes by alteration of DNA. The primary predictions of Darwin can therefore be considered the existence of and mutability of DNA information, though other scientists (e.g. Mendel) deserve credit as well.
The strength of evolution in the minds of modern scientists probably rests on four things:
It simply explains the massive amount of correspondence between structures in different species (e.g. limb structure) and the "family tree" of Linnaeus, as well as the similarity and dissimilarity (in the correct amounts) between the genes of the various species.
It predicted and continues to allow us to assess the change of disease bacteria under the operation of antibiotics.
It predicts what we will dig up from the ground. We dig up intermediary forms of existing species often and with the frequency that would be expected statistically given the tiny amount of land that can be excavated for fossils each year.
Some parts of the theory are mathematically necessary, resting directly on principles of statistics the same way that the Second Law of Thermodynamics does. From these principles, rates of change can be predicted, and these are verified within experimental populations (microevolution). Microevolution is not considered a theory as much as a law or process, within mathematics.
Macroevolution is the theory that says that species today derived from a common ancestor that lived billions of years ago. Microevolution can be "proven" deductively from axioms of mathematics and facts about modern organisms. Macroevolution is not proven, but the differences between species are within the range that could be predicted from microevolution given the time frame of billions of years across which the change is supposed to have occured. This does not mean that microevolution requires this to happen. You cannot prove macroevolution given microevolution.
I should point out that the supposed conflict with Genesis has nothing to do at all with any of this. That comes out of geochronology and depends not at all on evolution. Indeed, evolution requires old earth as a prerequisite and did not arise as an idea until there was already a large community of scientists who believed the world was millions of years old. The conflict with biologists seems to be a kind of historical accident. Thomas Huxley seems to have chosen evolution as a wedge to drive into theology after already deciding he was an atheist. Geology generated a large number of old-Earth Christians in the latter part of the 19th Century. At the same time, there were people in Europe re-interpreting Scripture for political reasons, and they got mixed up in WWI, and this inspired some Americans to challenge that non-literal interpretation of Scripture was a cause of political agression. Since Evolution rested on a geological claim that itself required a non-literal interpretation of Scripture, it got picked up into the politics of the War and its impact on America. I don't know the details of this in terms of what scientists stood where and which theologians said what, but I can't imagine it as a friendly situation for any party.
In any case, the dispute between science and religion far precedes evolution. The business about Galileo and the Catholic Church was famous long before Darwin.
Sentio ergo est.