Primary sources and creationism

Chad at Uncertain Principles has an interesting post up about the difference between the humanities and the sciences with respect to primary sources. I was all set to make a short comment, when it occurred to me that what I was about to comment on actually spawned a more interesting thought:

My comment was going to be that a critical difference between many (most? all?) humanities primary sources and those in science is that, in science, the primary sources (especially old ones, like Principia) are more than likely no longer totally valid. Once Nietzsche wrote down his ideas, they were there--it's not like someone could come along and "disprove" them. That's the whole point; they're subjective. Most humanities primary sources are--the point of them is to present a position and defend it, in one way or another, but the position and the defense are both subjective. They might be more or less well-supported or more or less relevant, but they're still opinions, and therefore can't be disproved.

The same can't be said for many (most? all?) science primary sources. No one who knows any better claims that The Origin of Species is completely in line with modern evolutionary theory, because we've made discoveries since it was written. (I.e., Darwin didn't have all the facts. Neither do we today, which is why biologists in 150 years probably won't be citing papers published today as definitive references.) Not having read Principia (or even Cliff's notes of it), I can't say that's the case for it as well, but I would imagine it would be. Even in my relatively specific field, there are a few "primary" references that a lot of people go back to, but only for certain things--because the rest of the article has since been replaced by something more specific. This constant reexamination, replacement, updating, etc., of the "going thing" is a fundamental part of science, and it's the reason that it's considered questionable in a lot of fields to cite papers that are more than a few years old: we might have learned something since then that totally overthrows the previous paper. (The time scale of "acceptably recent" varies field-to-field, but it's always there.)

This led me to a thought: I'm wondering what fraction of the struggles we have with creationists might be due to a fundamental difference in the perceived importance of primary sources. A lot of creationism "arguments" against evolution are based on Origin, even though any competent biologist (or, really, any intelligent person who's taken high school biology) should be able to tell you that a great deal of the text in Origin is only somewhat correct, if not flat-out wrong. But a lot of the people arguing against evolution come from backgrounds that are, shall we say, not steeped in the fundamental concepts of science. (This isn't to say there aren't scientists who are creationists; there are. But my impression is that the vast majority of creationists are not scientists and have very little scientific training.)

How much of the problem could be attributed to creationists being more familiar with the humanities "method", and therefore reading the "original" texts and interpreting them, without bothering to think about anything that's come after them? It's completely appropriate in, say, philosopy or literature to read a primary source and then draw your own conclusions and opinions about it. And your opinions are just as valid as those of others who have read the same text and drawn different opinions. (Which isnt't to say there aren't "accepted" interpretations of many famous works, or that dissenting with those interpretations won't open you to ridicule or censure.)

How many creationists who think evolution = Darwininsm read Origin, interpret it in light of common knowledge, and then view works based on Origin (i.e., most of modern biology) as simply others' opinions?

I don't think this is the primary problem or stumbling block; I think that's more likely to be a combination of a poor mainstream understanding of the nature of science and the tendency of creationists to be indoctrinated into an absolute belief system. But I think this also might be part of it.