A friend's Facebook status called my attention to a complaint about religious discrimination in that the Institution for Creation Research is being denied accreditation to give degrees in biology. I started to compose a reply to post in the comment thread there, but decided to write an essay here instead. But I'm going to start out by talking about a very important concept in physics: energy.
Energy's a pretty strange concept, when you think about it, and it doesn't help that the word is misused in so many ways. To a science geek like me, energy is measured in joules, kilowatt-hours or electron volts, so I bristle when someone starts explaining acupuncture and translates the word chi as "energy".
But even a simple, concrete unit like a joule is surprisingly abstract. It's not exactly an obvious quantity, like mass or distance or time. Nor is it directly observable; all our experiences of energy are inferred from our observations mediated by matter in some way. Energy is entirely a derived quantity, and the joule is a derived unit, defined as a kilogram meter squared per second squared. (You can get this by noting Einstein's famous formula, E=mc^2: mass times a squared velocity). We talk about potential energy, kinetic energy, thermal energy, energy stored in chemical bonds or atomic forces, the energy of photons, but in all cases we calculate the quantity through indirect means.
So ultimately, energy is an entirely theoretical quantity, never directly observed but so completely pervasive in everything we do that no one would dream to deny its existence. Physics just wouldn't make any sense at all if we didn't postulate this mysterious energy stuff. In fact, this theoretical quantity is so deeply established in our understanding of the world around us that most of us don't even realize that it's really a completely theoretical concept. Certainly no one would seriously say that energy is unscientific because no one's every actually seen the stuff, and anyone who did say that just doesn't understand what "scientific" means. And it may well be that energy doesn't exist, and our current physical theories are just a happy accident that happen to give good results, and a better, more parsimonious theory will come along some day that gives better predictions with fewer postulates, but anyone who did make the radical claim that modern physics is wrong because there's no such thing as energy would quite rightly be discounted as someone who just didn't understand physics. Unless she could provide that better, more parsimonious theory, which would be a staggeringly impressive accomplishment.
Now, the whole point of accreditation for academic institutions is to try to provide some assurance that a person who gets a degree in physics actually understands something about physics. That generally requires that the faculty providing the instruction should know what they're talking about, and if your faculty is trying to make a go of it without reference to energy, they may be teaching something but it probably isn't physics, and therefore should not be accredited to give out degrees in physics. (If they do have that more parsimonious theory, then they should not only be accredited but awarded Nobel prizes at the very least.)
It's important to note that this isn't strictly speaking about belief, but understanding. You don't need to believe in quantum mechanics (Einstein certainly didn't) or relativity to be a physicist, but you should at least understand the theories well enough to be able to provide legitimate criticisms, or to admit that your objections to it are basically intuitive, aesthetic, moral or otherwise unscientific (as with Einstein's famous statement about God not playing dice with the universe.) If you criticize the theory based on a clear misunderstanding of it, though, you call your expertise into question. Just as someone who claims to be a physicist yet denies the existence of energy is probably just profoundly ignorant of physics.
Which brings us at last to evolution. Like energy, large scale evolution has never been directly observed (though unlike energy, small-scale evolution is observed all the time, from antibiotic-resistant infections to African cichlid speciation). And I do not exaggerate to say that just as energy is to physics, evolution is absolutely crucial to modern biology, as evolutionary theory provides a cognitive framework that gives order to and makes sense of all of the observed data so far.
Again, it's not about belief. You don't have to believe in evolution to call yourself a biologist, but if you clearly don't understand the theory, you have no right to be recognized as an expert. And this may sound unnecessarily harsh, but every single creationist criticism of evolutionary theory I've ever heard (with one exception that I'll get to in a moment) has been based on a profound (if in some cases subtle) misunderstanding of the theory. In other words, creationists who use these arguments demonstrate that they literally do not know what they're talking about. And that means they are not in any way qualified to be hold degrees in biology, much less to be accredited to grant them.
I mentioned there was one exception. The only criticism of evolution I've ever encountered that didn't betray a grave misunderstanding of the theory goes something like this: "It may well be that the theory of evolution is the best one available so far to explain all the observed data, but it still feels wrong to me because it conflicts with my deeply held beliefs or intuitions that are not themselves scientific." That's the same form, essentially, as Einstein's objection to quantum mechanics; it just felt wrong to him that random chance could play so fundamental a role in the basic structure of the universe, notwithstanding that there was no solid scientific basis upon which to object to the theory. Likewise, one might feel intuitively that evolution is wrong because it's aesthetically unsatisfying, or one might believe it is false because one is committed to a literal reading of the Book of Genesis, or that it has destructive moral implications, but none of these are valid scientific objections, and none of them stand in the way of actually understanding the theory even if one happens to believe it is wrong.
Nor do any of these objections stand in the way of accreditation. There are probably lots of biologists who feel intuitively uneasy about some of the implications of evolutionary theory (and I'm working on a post about one of these implications I may get around to finishing in a few days), but they understand and apply the theory, and teach it, and they know what they're talking about. There are undoubtedly physicists who are somehow, deep down, convinced that relativity or quantum mechanics or both just somehow must be wrong, but they know what they're talking about. There may even be physicists who doubt the existence of energy, but they still have to know what they're talking about.
The reason creationist organizations like ICR don't get accredited to grant degrees in biology is not that they're uncomfortable with evolution. It's simply that when it comes to biology, they don't know what they're talking about.