I know exactly how you feel. I ended up posting on Facebook that God values honesty and integrity more than He values our doctrines about the age of the earth or evolution.
The point I make to my YEC friends is that any claims they make about science can be fact-checked and potentially shown to be demonstrably untrue. I tell them that claims that can be falsified will just undermine their credibility in the eyes of anyone who checks them out or is confronted with evidence that contradicts them at any stage – either during their education or while they’re witnessing to their friends.
The thing is, many YECs don’t even know YEC itself that well – they just see some Answers in Genesis headlines on Facebook and forward them without even reading them. Most of them have never even heard of the RATE project (and when I tell them about it, they think it’s an atheist parody) and it’s common for them to come out with arguments that the Big Three YEC organisations tell them not to use – such as moon dust, Paluxy river bed tracks, or what have you.
Here are a few things that YECs need to know as far as fact-checking their claims is concerned:
1. Historical science does not rely on unverifiable assumptions. Scientists solve the “were you there?” problem by (a) making testable predictions from them, and (b) cross-checking studies whose assumptions are independent of each other.
Anomalous results and discordances do occur from time to time, and the YEC organisations tend to make a big thing of it. However, this just proves that there are corner cases where the methods can fail – usually for well-studied reasons. They fall far, far short of proving that general cases are consistently wrong by up to six orders of magnitude, as would be required to fit the evidence into just six thousand years. The fact remains that concordance happens far, far, far too often to be accounted for in a young earth.
2. Old earth ages do not come from old earth assumptions. Much of the evidence for an ancient earth comes from searching for oil. Geologists need to know how both how old the oil is and its thermal history. Too young, or too cool, and it will be “premature,” still solid, and impossible to extract out of the ground. Too old, or too warm, and it will be “post-mature,” generally uneconomical, and at worst baked into oblivion. Geologists are under strong pressure to come up with ages that are accurate, not ages that are ideologically convenient. (See the post “Can Young Earth Creationists Find Oil?” on the Age of Rocks blog for more details.)
3. The evidence can not be interpreted either way. YEC attempts to do so end up resorting to absurdities so extreme that even some YECs I’ve spoken to think they’re an atheist parody. The RATE project concluded that because billions of years’ worth of nuclear decay has happened (their own admission), nuclear decay rates must have been much higher in the past. However, this would have released enough heat to boil the oceans and vaporise the earth’s crust many times over (again, their own admission) if it were even possible. Their attempts to work round the problem were even more spectacularly absurd.
4. There is no known solution to the distant starlight problem. Every attempted solution resorts to bizarre esoteric physics that is unsupported by any evidence, makes predictions that are not observed, and in some cases is based on very bad handling of historical data. Even if they were able to come up with something that stood up to scrutiny, they’d still have to explain why there are galactic-scale structures out there such as colliding galaxies or active galactic jets that show clear and unambiguous evidence of millions if not billions of years’ worth of interaction.
Incidentally, you may hear them claim that the distant starlight problem is the same as the horizon problem. This, again, is completely absurd. The horizon problem concerns the first three seconds after the Big Bang, the scale of the entire universe, and physics that is poorly understood. The distant starlight problem, on the other hand, concerns the present day, scales just a fraction of the size of our galaxy or bigger, and physics that is very, very well established.
5. Human and chimp DNA really are 98% similar. I’ve seen some claims that this figure is based on cherry-picked subsets of the respective genomes. This is not true – whole genome comparisons have been carried out for over a decade (the first being published in Nature in September 2005). Comparisons giving lower figures such as 70% or 85% are based on flawed comparisons that configured the comparison software in ways that reported that human DNA is just 89% similar to itself.
6. DNA similarities include features such as endogenous retroviruses and pseudogenes. Endogenous retroviruses are DNA sequences that have clear characteristics indicating that they originated as viral infections which inserted their genetic code into reproductive cells (sperm or eggs) and then were passed on through the generations. There are several of these ERVs that occur in exactly the same place in the genomes of multiple primates, humans included.
Answers in Genesis has an article where they attempt to explain ERVs away. It makes a big thing of the fact that ERVs do actually have some function, which doesn’t answer the question of where they came from in the first place. It also makes the completely absurd claim that ERV similarities are just an assumption based on evolutionary presuppositions and circular reasoning. This is nonsense: ERV similarities are a direct observation.
7. Soft tissue remnants in dinosaur fossils are very rare, and only consist of the most durable components such as collagen. There are no reliable reports anywhere of DNA having been recovered from fossils dated at more than a million years or so. Since DNA can easily survive intact for thousands of years in ideal conditions, and will still be present (if fragmented) even in sub-optimal conditions, we would expect dinosaur carcasses with vast quantities of sequenceable DNA to be very common in a 6,000 year old earth. But they aren’t.
I tell my YEC friends that the only way the earth can be six thousand years old is if it were created with evidence for 4.5 billion years of history that never happened. Similarly, the only way that humans, chimpanzees etcetera can have independent ancestry is if we were created with evidence for a common ancestry that again, never happened. There are theological problems with this approach (the “omphalos hypothesis”) of course, but if they really are that wedded to a young earth, that’s the only scientifically coherent option that they’ve got.