Creationist inconsistency when inferring relatedness

I asked this of Aaron. I didn't get an answer though.

Whoever wrote it seems to be making a distinction without a difference. What's the difference, really, between knowing that something is accurate, and knowing that it's well-supported by the evidence? Evidence is how we know things. That hardly explains why a crocodile is genetically closer to a hummingbird than it is to a Komodo dragon, or why a coelacanth is more like a dog than it is like a dogfish. The reasoning, such as it is, seems to be "If we can't know one thing, concerning which we have no evidence, then we can't know something else, completely different, about which we have a lot of evidence". That hardly seems to hold water, does it?Edited by Dr Adequate, : No reason given.

Sure, sometimes we have to learn to live with our ignorance. But also, sometimes we have to learn to live with our knowledge. This is one of those times.

Well, we always have permission to construct a theory about anything. The question is, do we have "permission" to believe it? Does the theory fit the facts? In the case of evolution, yes, it does. The question would be, when a few simple premises explain all the observations, is it rational not to believe it?By analogy, suppose someone denied the theory that lightning causes thunder. If we ask him, then, why they are found in association, he replies that it's just one of those things, it's a coincidence. Is that a rational stance?Getting back to the actual topic, we have a method which produces the right answer when we can test it. Genetic analysis reveals that I'm closely related to my brother, less closely related to a white person chosen at random, still less closely to a Japanese person. It tells me that dogs are related to wolves, it tells me that domesticated strawberries are related to wild strawberries, things that no-one doubts. It tells me that donkeys are related to horses, a proposition which is even believed by about 50% of creationists. So, is it rational to refuse to believe the results of the exact same method when it tells creationists something they don't want to hear? On what basis?By analogy (I like analogies, sue me) suppose someone acknowledged that trigonometric methods of surveying are perfectly accurate every time we use them to measure the distance to a mountain peak or a church spire, that in these cases they are always correct, and always give the same answer as we get when we use a tape measure; but then he insists that the same method is always wrong when we use it to measure the distance to the stars, which he is convinced are very close to us. Now, does he have "rational permission" to reject this method when it starts giving him answers he doesn't like? Or do we have "rational permission" to follow this method where it leads us?

Then it is wrong. Well yes, to say that person A is the same person as person B, you need the DNA to be identical. You need less similarity for "is the brother of", less still for "is the same race as", less still for "is the same species as". If biologists propose that you need less still for "is the same Linnaean familiy as", then why would you draw the line there? That is not an indication that these similarities lack relevance, but rather an indication that we're distantly related to bananas.Edited by Dr Adequate, : No reason given.

Or ... evidence. Also, these so-called "scientists", not content with telling you about your ancestors, tell you that you yourself were once an infant. Are you supposed to start shitting yourself and crying when you want to be fed? Well, things can be true even if you don't like the sound of them.What would a Christian apologist say, I wonder, if someone used the exact same argument against (for example) the doctrine of original sin, calling it "derogatory to human status"?Is it not, after all, derogatory to humans to say that "the imagination of man's heart is evil from his youth" (Gen. 8:21) and that "The human heart is the most deceitful of all things, and desperately wicked" (Jer. 17:9)? If being derogatory is the test of truth, we can throw the Bible away right now and look for something better.But surely the apologist would say that human pride is a sin inspired by the devil, rather than a yardstick to discover the truth of things.