That’s the blunt truth about how I see it. I’m not talking about the political situation of various attempts to slip it into schools or its public relations, though it’s still applicable: The promoters try to gloss over the fact that it’s religious and try to make it look vaguely secular, meanwhile they can’t keep the fundie hordes from revealing the sectarian motives.
My major point is that Creationism as a hypothesis is in a state of chaos. If a person identifies himself as a Creationist, that doesn’t tell us what he believes or gives us insight into what he’s likely to believe, beyond the vaguest of details. Evolution and inflationary cosmology are better defined. I believe in those theories because of the evidence, and knowing that, you can reliably predict that I believe:
- The universe is 13.7 billion years old. The Earth is 4.6 billion years old.
- All life is related in a large nested hierarchy, like a branching tree. You won’t find any examples of large multicelluar organisms (like animals) that would fit in more than one branch. No cat-dog hybrids without deliberate genetic modification, for example. The closest you’d get naturally is a cat, with the genetic features that define it as a cat, that superficially resembles a dog or the reverse. The descendents of cats are still cats, though as deep time passes and modifications pile up, they may become very strange compared to our current idea of a cat. Even so, they’d still bear the molecular and morphological legacy of cathood.
- Fossils are arranged with the oldest species on the bottommost layers of rock and the most recent on top. By comparing similar fossils up and down the rock layers around the world, we can infer relationships based on the shapes of their fossilized bones and compare these relationships with other lines of evidence, such as molecular biology, and find a consistent picture. This is what we find.
- Most mutations are neutral, but some are deleterious, others are beneficial, and some are mixed because they affect linked traits in different ways. The beneficial mutations will generally have better chances of proliferating, while the negative mutations will more likely die out.
- There is no “great chain of being” with humans at the top. We’re just one more successful species and there will be others, possibly including a future species descended from us. Evolution wasn’t “done” when we showed up.
These are a lot of “big picture” consensus beliefs. These are the kinds of things that experts will put into textbooks and popular science media. If someone claims to believe in evolution but asserts something contrary to these sorts of ideas, the experts would seek to correct the misunderstanding and/or challenge the dissenter to prove it with scientific evidence. And this is just the big picture stuff. There’s a massive wealth of details that have a strong consensus that remain consistent with the theories.
In other words, science has converged on these beliefs. This is what we would expect if a reliable testing method (science) was used by many different people from different backgrounds (scientists from around the world), to reach conclusions about objective reality. The history of science is one of increasing consistency and accuracy as more evidence comes to light. The consensus changes in a predictable, logically necessary manner.
Of course, there isn’t absolutely perfect agreement on all issues, but the arguments that do occur between scientists are about increasingly finer and more nuanced details. You can still find large areas of general agreement between scientists who are on opposite sides of one of those conflicts. In evolution, there are many different forces in play: Natural selection, sexual selection, genetic drift, and so on. Biologists of different specialties may have heated arguments about the relative importance of those factors in the evolution of a species or trait, but you can reasonably count on them to acknowledge all those forces exist.
And now, back to Creationism. If I stumble on some Creationists while web surfing, I have much less confidence in my ability to predict their answers to important questions about cosmology and the history of biology. There are a lot of mutually exclusive claims, and skimming the well known Talk Origins’ Index to Creationist Claims brings up a lot of them. I’ll point out that the page was last updated in 2006, and I can’t think of anything about Creationism that would necessitate further updates. Let’s go over a few examples:
Age of the Earth: Answers range from about 6,000 years to 4.6 billion. This is one of the bigger divides in Creationism: Young Earth Creationists (YEC) and Old Earth Creationists (OEC).
The age of the universe and distant objects: This is one of the classic things Young Earth Creationists have to come up with an explanation for. Their problem is that they’ve come up with multiple explanations and there’s no clear favorite. How did the light from those distant stars get here? Some say their god created light that was already en route to Earth. Others say the speed of light used to be much faster. In the ancient days, stars were holes in the sky, rather than distant fusion reactors. Of course, another popular answer is that the evidence for the distance of those objects is all a hoax perpetuated by a satanic worldwide conspiracy.
Radiometric dating: One of the core premises (which is backed by all the evidence thus far) behind radiometric dating is that isotopes have a consistent half-life and thus a predictable rate of decay that can be used to measure the age of something. Creationists sometimes try to get around this by asserting that the rate of decay used to be much faster. (Which would mean a lot more radiation in those days.) Others say the universe was just created with the isotopes and decay products in just the right proportions to give the appearance of age. And, of course, there’s the conspiracy assertion.
Fossils: Some say they’re distributed by the animals’ abilities to flee from the rising flood waters at the time of Noah, and altitude of habitat. (They’re not.) Others say they were somehow filtered by complexity by the flood waters. (They’re not.) Some say their god created the fossils to test faith and to troll scientists with the deception. Others say the devil made the fossils. Others say scientists planted the fossils.
Noah’s Ark and genetic diversity: Some claim that Noah brought aboard a few vaguely defined “baramin” animals that then evolved and speciated at super speed, somehow acquiring diversity that would be absent from such a genetic bottleneck. Some say some animals survived by living on floating islands of plant matter, lowering the demands of the Ark. Some say the dinosaurs were on the Ark. Some say the dinosaurs were left to drown. Some say there were no dinosaurs in the first place.
Noah’s flood and the source of the water: Vapor canopy. Comets. Hydroplate. Runaway Subduction.
I could go on and on if I really wanted to go over all the crazy Creationist ideas I’ve read about over my years as a skeptic. It’s even common to see a Creationist change their beliefs repeatedly over the course of a conversation as they’re criticized. This tells me that Creationists either don’t think about the implications of believing contradictory ideas and/or that they’re just trying every alleged “zinger” in their playbook to justify their dissent from the scientific consensus, as dictated by rhetorical convenience, rather than logic and evidence. There is no Creationist consensus beyond a few bare bones. Creationism is still at the mercy of the chaotic whims of fashion.