Evolution - Here I Stand! I Can Do Nuttin' Else.
I got an interesting comment about my last post so I thought I would answer it in the form of a post. I hope this does not breach some kind of blogging etiquette.
I would like to turn your arguments in the comment thread of your last post back to you.
"For those of us that not only accept evolution but are interested in it..." My question is simply: why have you seemingly put your skepticism aside for the purpose of "accepting" evolution? Before I'm accused of being a "creationist", note that I have heretofore made no such claim. It just strikes me as inconsistent for you to assent to a theory that has yet to be conclusively proven. Granted, the preponderance of evidence may strongly suggest it's validity. I postulate that one relies more heavily upon conjecture to bridge the gaps in the fossil record than one for whom the Bible is supporting evidence for the existence God. ;)
Good question. It all boils down to what I have personally learned and the fact that our standards for whether or not a theory has "yet to be conclusively proven" are different.
I have been interested in many fields of science to varying degrees since childhood . I am even currently working on a more formal education in Biology at University after being in the civil service for a spell. However I should go back a bit in my education to explain how I accepted evolution.
There came a point in high school where I had been reading about Darwin on my own (school I was at had a Catholic nun on the board so the science teacher did not dwell long on the topic) when it suddenly clicked as to how things like survivability and viability of an organism would affect how often it would be able to pass on its genes and thus how widely those genes would be expressed. If new genes were emerging at a slow but constant rate (I would only learn how later in my education), there could be no other outcome than for those genes to be either screened out by killing the organism or preventing mating, or spread into the greater population where they would either increase or decrease in frequency based on the probability of survival for all individuals that had them. Over time, all non lethal genes would be tested and either pushed out or achieve some fraction of penetration in the population. For really useful genes, that fraction would be 100%. What else was possible? Could genes and combinations of genes that made an animal more adapted to its environment, more likely to survive and reproduce become less prevalent over time? Would traits that left one unable to find mates or food gradually take over a population. The logic seemed pretty unassailable.
As I went through some university (followed by a temporary escape from academia) and also pursued my education on a personal level, I was aware that the theory was not accepted by a large fraction of people, almost all of whom were outside the scientific community like philosophers, theologians, normal every-day people and graduates from Bible colleges. Those few who were scientists tended to be physicists, mathematicians... people with little or no background in biology. While this itself does not discredit their arguments it is worth considering their lack of education in the field they are criticizing. I read the arguments by creationists of various types and backgrounds - young earth, old earth, left-wing relativists, right-wing fundamentalists, Christians, Hindus, Intelligent Design theorists and all of their points were easily and repeatedly addressed by evolutionists. This did not dispel the points though; they kept repeating the same tired criticisms year after year like appealing to thermodynamics (as if earth were a closed system). Only occasionally coming up with something new but equally fallacious.
I can't remember exactly when it happened that I went from feeling that evolution was the most likely theory to account for the natural world to being certain that it was the only theory that was consistent with everything I had learned and discovered. I gradually became struck by the fact that all of these different fields I had been interested in (due to their fundamental significance to questions like: Who are we? What is life? What is reality? etc.) were all pointing in the same direction. Observations from fields including biology (from molecular and population genetic to embryology to cellular, right up to the ecosystem level), anthropology (paleoanthropology, primatology,) cosmology, computer science, geology (to the limited extent that I was interested) were all delivering information that fit in perfectly with the evolutionary model and yet were virtually impossible to account for in the absence of that model. Is it likely that God or some other power would have created a universe that was perfectly and completely designed to look like an evolutionary one and which had laws of physics and principals of biology that would allow - no insist - that evolution happen, and yet this same entity would somehow prevent evolution from occurring?
As far as the "gaps in the fossil record" and the "lack of intermediate fossils" as opponents of evolution often claim exist... quite frankly, it is not entirely true. It is true that there has never been a discovery of millions of individual fossils from successive species, lined up like a Soviet bread queue so we can see a skeleton from every thousand years and play them back like a flip book. That being said, the museums and universities of the world are filled with drawers and drawers full of fossils that show individuals of species that share more traits with those organisms that are found in similarly dated rock and fewer with those that are further removed in geological time. Many intermediate species have been found.
In the ape to human branch of the fossil record we should expect there to be few fossils due to the short geological time frame involved and yet we do have a significant number of intermediate fossils. Take a look at this site. Notice how the top row of modern ape skulls is so distinct from the lower row of humans. Then look at the middle rows. What possible reason could there be for finding old skulls that share traits of both apes and humans even though neither modern apes nor humans are seen today with skulls of this shape and yet find no modern looking human skulls before about 180,000 years ago? Given the amount of evidence for evolution of other species like mammals, amphibians etc. and the transitional forms in the fossil record (not to mention egg laying mammals like the platypus), does it really take much faith or "conjecture" to conclude that these skulls belonged to various intermediate proto-humans?
I have not gone in to the topic of vestigial organs and tissues or the genetic evidence for evolution like how neutral mutations accumulate in a manner that can be used to compare species' genetic similarity and how these changes correlate with the fossil record to a such a degree that would not be expected without evolution because I am getting tired now. Perhaps in another post.
Skepticism is not an absolute law but a set of principals. Believing something in the absence of sufficient evidence goes against these principles. Believing something despite sufficient evidence to the contrary is also. How much evidence is sufficient though is a judgment call.
When all of the information and observations that I have been able to obtain (a considerable amount, I feel), not only support a theory but are in many cases are incomprehensible without the theory; when all arguments and opposing claims I have seen are inconsistent with reason and available evidence; when there are no competing claims, I am willing to conclude that the theory has been proven conclusively. For any theory to displace it or for any argument to challenge it in my mind, I would have to see how it could account for all or at least much of what evolution does. For instance if an elf were to appear, prove to me that he could make universes and explain to me why and how he had created a universe designed to trick us, I would certainly reevaluate the modern evolutionary model. I would not however feel foolish since he seems to have put on one hell of a show.
That does not mean that the evolutionary theory is finished. There will no doubt be things we learn about evolution as we continue to study life both past and present. In fact, only a few months ago I was reading about the work of a mathematician with computer simulations that showed how a species can be divided into two separate breeding populations by a single selective pressure long before any mutations occur. Before this many biologists assumed that a population would need to be separated by geography and accumulate mutations before they would be unable (or unwilling) to interbreed. Not only did the simulations support his point but it made perfect logical sense as well. I have been meaning to do a post about it as soon as I can track down the article.
In closing here are a couple of extra links on the issue. The first one is my favorite because it represents an entirely new form of evolution to study.
P.S. I will be away for a few days so I may or may not post this week. I am trusting the Internet to be on its best behavior in my absence so no monkey business!