More on the dishonest and tiresome tactics of Creationists. This time I want to cover the overly used tactic of "moving the goalposts." An example of this type of argument would be in talking about transitional fossils. Evolutionary theory states that whales had land-dwelling ancestors, so the fossil record should have transitional forms that show the gradual change from land-dwelling to sea dwelling. Now there are several linear fossils in the record, showing a gradual change from land mammals to sea-dwellers. Yet each fossil creates two more new gaps and the challenge now is satisfying each of those gaps, thus moving the goalposts.
Creationism vs atheism
The first blatant goal-shifting exercise done by creationists is to shift the debate away from whether evolution or creation best fits the evidence, and take the debate to whether God exists. For if the bible is true, then it's God's word. And if it's God's word, then it's truth. And if it's true then creation must be true and to hell with any contrary evidence. This technique is part of the now infamous Wedge Strategy as a means of trying to weasel creationism into public science classroom and ultimately bring people to Jesus. So now the debate is between naturalism and divine intervention, and of course in this instance it would be split down religious lines (Hence a wedge.)
The shift from science to philosophy is not going to make the scientific evidence any less real, or any less supportive of a particular theory. Whether God exists or not is not definitively resolved by being able to explain our biological origins, and even if it was it wouldn't make any of the lines of evidence any less valid. The transitional fossils are still there, the genetic code still shows many different evidences of common ancestry, the observations of natural selection and adaptation still exist, the geographical distribution of life both now and in the fossil record still tells the same tale. As the bumper sticker says - "We have the fossils, we win!"
Usually anyone who tries this strategy will break away from science and into pseudo-history. Because apparently if you can show that if a couple of names and places that are in the bible are also in other historical documents, then the bible must be true. Though this position breaks down with all the archaeological evidence that goes against the bible, and even the bible itself is littered with contradictions. And even if the historical events of the bible had validity, it doesn't mean that the miracles associated with those events happened. Faith in creationism is not faith in God, it's faith in an inerrant bible.
Science doesn't allow for the supernatural as an explanation as it's an untestable assertion. Saying "God did it" adds absolutely nothing to the endeavour of human understanding and it takes proof to one higher layer of abstraction. Showing God's hand in nature not only requires demonstrating the event of divine intervention, but puts the burden of evidence onto demonstrating that there's not only a god but the Judeo-Christian construct of god.
A theory of everything
Evolution explains a lot of things, to sum it up as an explanation for the diversity of life sounds like a cop-out. But given the magnitude of what constitutes the process of life, it's explains so much. But for all it can explain, there are many things evolution cannot explain nor does it attempt to. It doesn't explain the origin of life, it doesn't explain how planets form or how gravity works. It doesn't explain where the universe comes from. To anyone familiar with the theory, these are nothing more than obvious truisms. But the 2nd blatant goal-shifting exercise by creationists is to rest the truth of evolution alongside science without the same evidential weight behind it.
This line of thinking leads to an invalidation of evolution through it's association with more speculative hypothesises. Without an explanation for the origin of life, it doesn't negate the evidence for common descent. Unless creationists are positing that God created the first cells from which all life came about, the creationist position of each life-form (and specifically humanity) being hand-crafted by God doesn't follow from a lack of explanation on the abiogenesis front. Likewise, the question of why there is something rather than nothing, i.e. The Big Bang, does not mean that one can infer that because the universe exists rather than not exists (meaning this question would not be asked) that God created it all 6000 years ago when quite clearly the universe is over 10 billion years old.
Again this is a way to not assess evolution on its own merits, instead the merits of whatever hypothesis evolution is tied to. Abiogenesis is a necessary precursor to evolution, it's an as yet unknown process that happened sometime between 3.5 and 4 billion years ago. It's important to understand what evolution is, and by doing so it should become obvious of what evolution isn't. It's not a theory of everything, it's not mean to explain the process by which the first cell came about, nor is it there to explain why there is something rather than nothing. Instead evolution is there to explain the diversity of life.
It's understandable why evolution is seen by some as a theory of everything, it takes away one of the most fundamental roles God was alleged to have played in humanity's history. If evolution can explain away why we are here, then it does harm some people's image of God. So in that respect, when evolution is attacked for being an inadequate theory of everything, it's an indicator of how fundamental our origins are to how we define ourselves and our place in nature. So without a God explaining our origins, that would surely mean that other roles God played have to be accounted for as well. Thus evolution is understood as being synonymous with nihilistic materialism.
The shifted target is now explaining all of reality without invoking a supernatural power, something that evolutionary theory cannot satisfy, and something that with our limited knowledge and observation point cannot currently be satisfied. So while the evidence for evolution is overwhelming, the shifted requirement for evidence means that those invoking a supernatural power will never be dissuaded - despite the overwhelming evidence contrary to their assertions.