The reason its not science is because young earth creationism does not even follow the same methodology as science, so even if it were legitimate it wouldn't be considered science. You see science starts with no presuppositions of how the world is supposed to be, then looks at the evidence and forms a conclusion; presuppositions may exist but they are ignored. Science draws the conclusion after gathering the evidence. Young Earth Creationism starts out with the conclusion that earth is 6,000 years old and was reshaped by flood 4400 years ago and then find evidence to support the conclusion they have already come to, then they have to force-fit all science into this conclusion. They even freely preach this position; here is a quote from the leading creationist Ken Ham;
When someone tells me they want ‘proof’ or ‘evidence’, not the Bible, my
response is as follows:
‘You might not believe the Bible but I do. And I
believe it gives me the right basis to understand this universe and correctly
interpret the facts around me. I’m going to give you some examples of how
building my thinking on the Bible explains the world and is not contradicted by
science. For instance, the Bible states that God made distinct kinds of animals
and plants. Let me show you what happens when I build my thinking on this
presupposition. I will illustrate how processes such as natural selection,
genetic drift, etc. can be explained and interpreted. You will see how the
science of genetics makes sense based upon the Bible.’
At first glance Ken Ham's view does seem reasonable after all we do interpret everything according to our own biases don't we? Also This perspective allows a person intelligent or not to comfortably except any view and feel perfectly comfortable with it, even though to an outside observer it may obvious that the person is mistaken. Ken Ham has successfully crafted a way that you can believe whatever you want and not have to deal with what the facts have to actually say at all. If I didn't have such high scruples and respect for rational inquiry I would accept this view; it is very, very comfortable, but is it rational? Is this view really how we find truth, is this really how science worked all along? In any area? Why if this idea were true archaeology would be impossible since we would not know anything about this civilization except what they left behind, "we weren't there." The past before human experience can be known.
Suppose I were out hiking in the mountains and I came across the body of a deer which had fallen in my path, also suppose after examining it I found that it was torn apart and showed teeth marks, I would say it must have been eaten by wolves. At this point the only evidence for a wolf attack is the fact that it has teeth marks on its body (as well as the fact that its body was in several pieces). Well what else can I do? Suppose I were to look for wolf foot prints, the deer looks like it was killed relatively recently so there should still be foot prints in the area; so I look around and lo' and behold, there are wolf foot prints all around the place. Also lets say I have to spend the night around that spot, and while I am uneasily trying to sleep I hear wolves howling. This is not a perfect analogy but it shows you can indeed tell what happened in the past without having to here it from an eye witness. Now I may not have the entire picture but I have the basic idea; the deer was attacked by wolves, large parts of its body were eaten. So I can get some idea of the past, unlike how Ken Ham seems to think that we have no way of knowing.
Also there are several problems just with his last few sentences.
--Science does not make sense under his interpretation of the bible
--The bible was never meant to be a science textbook, the bible itself makes this obvious, if it were meant to be a scientific text, the parts of the bible discussing scientific topics (the origin of the universe for one) would be no doubt more detailed.
What do we have here in this view that young earth creationists embrace? Well if this is true and our presuppositions determine reality, then there is no objective truth. You can go ahead and claim the bible is the truth in this view but that is just you assertion, there actually is no substance to it, a Muslim could just as easily claim that what the koran says is absolute truth and his position would be just as valid as your own. Unknowingly and unintentionally Ken Ham and his followers have bought into postmodernism, a view which is both anti-science and anti-Christian, both science and the Christian faith demand that there is a truly objective truth to which all truth can be tested against, otherwise both are in trouble. No matter how tempting an idea may be, we cannot accept postmodern ideas to justify its acceptance.
It must also be mentioned that this view has a general intolerance about it, Answers in Genesis will accept no other interpretations then their own, if you question it based on scientific evidence which contradicted it, you are now a heretic. If we are to make this view the normal view of the scientific community then we have just sentenced science and the scientists to prison, this isn't reconciling science and faith, it is placing science under the thumb of an unnecessary dogma. This isn't science being reconciled with faith, its more like science being oppressed by faith. What could happen if this view is accepted as the mainstream philosophical view on science? Scientists may be forced to rewrite all science into a particular interpretation of the bible, any evidence that truly contradicts their philosophical presuppositions will have to be rationalized or ignored, if they dare try to bring it up as a challenge to the particular view of the scientific community, it would be like a rerun of the Spanish inquisition.
Answers in Genesis says so itself that no theory if it contradicts their view of scripture can be legitimate, if it conflicts with there position it is wrong and that's that, no other examination required. And anyone who dares oppose there position will be fired from their job, lose their reputation and ultimately neither science nor Christianity will be helped by this theocratic control over the scientific community; both will be held back, perhaps for centuries.
Now I am not saying people don't have presuppostions, of course they dom its just they must be discussed in their proper place, in the realm of metaphysics, not in physical science.
I am not saying the AiG proponents all think this way or that somewhere along the line the next generation which holds this veiw might become the oppressors