Many years ago, on my old web page, I wrote a piece explaining the twin paradox of special relativity. More recently, I created a YouTube video with the same purpose. Now, I'm not a physicist, and don't claim to have a complete understanding of Einstein's theory at all. I just happened to stumble upon and share a way to think about the twin paradox in a way that made sense to me and that seemed to be consistent with what the experts say about it. (If I'm wrong, of course, I shall be more than happy to have a physicist set me straight on it.)
But a curious thing happens when you post something about relativity theory on the internet. You start getting email or comments from people who are convinced that Einstein was hopelessly wrong, and who try to explain how. Over the years I've had maybe a half-dozen correspondents on the subject. As I said, I'm not an expert, so I'm really not in a position to debate them about the theory generally, but I'm into thinking and reasoning generally, and I'm very interested in diagnosing the kinds of cognitive errors people (myself included) typically make.
In this case, I'm intrigued by the ways in which some people naively take issue with the views of the experts. Most of us, I'm guessing, would look at something like relativity or quantum mechanics, admit that we haven't really got a clue, and defer to the guy in the white lab coat scribbling formulae. But the ones who email me about relativity, at least, almost invariably seem to be convinced that they not only understand it, but understand it well enough to refute it. Relativity is just one example; somewhat more common are the creationists who argue passionately about how Darwin got it wrong. More troubling yet are the various conspiracy theorists, anti-vaxxers, sovereign citizens, climate-change-denialists and other similar movements, which not only are hopelessly confused about the actual subject matter but are actively doing real harm to themselves and others through their ignorance.
Don't get me wrong: I am not saying that one should accept without question whatever The Experts tell us. Sometimes the authorities are wrong, and in any event, we all benefit from healthy dialogue about theories and issues, because even a wrong theory can help bring us to a better understanding of the truth. It's vitally important, in a free and democratic society, that people feel free always to question the conventional wisdom. It's not disagreement with the experts I want to criticize here, but rather methods. There is a right way and a wrong way to be a skeptic.
In this post, I want to talk about the a particular error that's usually a dead giveaway that someone is not so much a brave dissident challenging the hidebound orthodoxy as a deluded crackpot. Specifically, it amounts to assuming that the experts are unaware of basic "common-sense" facts about their discipline.
It's a safe assumption that if something is common knowledge, an expert in the field is probably aware of it. For example, most people know that mercury is very poisonous, as are most heavy metals, so it's reasonable to assume that an expert in chemistry or medicine will also be aware of this basic fact. I suppose you might find some expert who believes mercury is harmless, but at the very least, even that expert should be aware of the widespread belief that it's poisonous, and be accustomed to having other people disagree on that point. If you tell someone that mercury is poisonous, the expert might say, "Yes, it is," or give an exasperated sigh before patiently explaining how that's a common misconception.
Yet anti-vaxxers will exclaim in alarm that vaccines contain mercury! MERCURY, for heaven's sake! I'm not sure how they expect physicians to react to this revelation: "Wait, what? I thought thimerasol was just a preservative! Good heavens, there's mercury in it? And mercury is poisonous?Why didn't anyone say something?!"
Give them some credit. They already knew that mercury is poisonous, and that thimerasol contains mercury, when they decided to use it. Just like a surgeon knows that stabbing someone with a knife is usually bad for them. And yet somehow, the surgeon knowingly goes ahead and cuts people open with a knife in order to treat them, because they know a heck of a lot more about cutting people and putting them back together than a random layperson does.
That's the thing about experts. They don't just know the really simple obvious stuff that everybody knows; they also know a bunch of complicated stuff that occasionally flies in the face of the obvious overgeneralization. Yes, cutting someone with a knife is usually bad for them, but it can be made less bad with proper preparation, tools and technique, and sometimes it's much less bad than leaving the condition untreated.
Lots of things are obvious to everyone, expert and non-expert alike. But if we could rely on the obvious in all instances, we wouldn't need experts at all. Experts are those who understand the non-obvious parts of their disciplines as well as the obvious, the things that not everyone knows. So if your criticism of the experts is based on their apparently overlooking something really, really obvious, stop. Do not assume they're idiots for missing what is plain to you, and tell them they're wrong. That is how crackpots act, and rightly or wrongly, you will be dismissed as one.
Instead, ask. "Wait, I thought mercury was poisonous? Why are you putting it in a vaccine?" Because then they can explain how the toxicity is much less when the mercury is tied up in certain kinds of molecules, and how the quantity involved is so tiny that even if it poses any risk it's far outweighed by the benefits of the vaccination itself, and if you've the time and patience they can go through the data with you and eventually you'll understand it like an actual expert yourself. Or, they might do what they actually did with thimerasol: "Well, it's actually quite safe, but since you're concerned about it, we can replace it with something that doesn't contain mercury."
Another way to put it is like this: it's okay to disagree with someone, but it's not okay to disrespect them, and assuming someone is so stupid as to be completely unaware of common sense notions of her area study is fundamentally disrespectful, and empirically wrong. Common sense does not trump expert knowledge. You don't have to believe the experts, but don't presume they're idiots.