Imagine you found a pretty crystal while on a hike at a park. Suppose that a few hundred meters further on the hike, you ran into another hiker and struck up conversation. In that conversation, you show them your pretty crystal: “Hey, look at this neat-o quartz I found!”

Suppose your new hiker acquaintance responds by saying, “Actually, that’s not quartz at all, it’s feldspar. When I’m not a nature hiker, I’m a geology professor and a licensed gemologist.”

Naturally, your reaction (assuming you are not yourself a geologist or something) would be to say, “I don’t think so. I still say it’s a quartz. It looks all… quartz-y!”

What? That wouldn’t be your reaction?

No, of course not. Such a response would be perfectly ridiculous. Disagreeing with someone who knows much more than you about a subject, based on nothing more than your own feelings or intuitions, would be the height of foolishness. Right?

So why are there so many evolution doubters and global warming deniers and other self-styled “skeptics” who feel perfectly comfortable rejecting the well-supported conclusions of the overwhelming majority of scientific experts based on nothing more substantial than their own uninformed convictions about the matter?

Whether it’s evolution or neurobiology or climatology, when someone has some preconception or emotional obstacle to accepting some conclusion or implication of scientific investigation – that is, when they just plain don’t like it – they often feel perfectly free to reject the conclusion for the flimsiest of reasons, or no reason whatsoever. As someone who cares about science in specific and expertise in general, I find this…irritating, to say the very least.

Of course, I fully realize that rationalization is a pretty nearly universal feature of human nature. (More, there is good evidence that rationalization is a trait shared by other primates as well – which is exactly the sort of scientific finding some people reject out of hand, circularly enough.) But the whole point of science – or at least one of the major features of science – is to serve as an artificial construct that filters out various sorts of prejudices and rationalizations as much as possible. Rationalization can’t stand up to the process where we do the math, do the experiments, subject it all to peer review (i.e. criticism by other experts, usually rivals), and repeat endlessly. That’s pretty much the whole idea.

Yet, when it comes to some pet belief they don’t want to give up – some conclusion at odds with a vested personal interest or emotional conviction – a vast proportion of people feel free to just toss that whole process out and stick with the flimsiest rationalizations imaginable for their preferred beliefs. Faced with the weight of all the evidence and arguments provided by all the experts who know a hell of a lot more than they do about a given subject on one side – and the weight of what they personally want to be true bolstered by some bullshit arguments generated by some guy on the internet who shares their prejudices on the other side – a frightening majority of people seem to go with their wishful thinking and against all the expertise in the world every damned time. (Don’t believe me? Go look at polling data about belief in creationism, astrology, psychics, and other patent nonsense.)

Of course, nothing in what I’ve said here implies that science is flawless, perfect, or that its conclusions are always correct. Science reaches wrong conclusions all the time, and fails to reach any conclusion at all on a given question even more often than it reaches the wrong conclusion. But errors and gaps in scientific understanding aren’t corrected in any way by people disagreeing based on their preconceptions, preferences, and feelings: Errors and gaps are corrected by more scientific inquiry! That’s how science works to correct itself, and that’s how human knowledge has expanded so vastly over the past few centuries.

All scientific findings are provisional, but that doesn’t constitute any kind of justification for someone who isn’t familiar with the relevant science to reject any given scientific finding. To say that a scientific claim is “provisional” means that we have sufficient justification to accept it as true until some further evidence and reasoning comes along which overrides the evidence and reasoning we’ve used to date. “Provisional” most definitely does NOT mean “I don’t have to accept it as true if I don’t want to ‘cuz it’s just provisional! So there!” Experts may sometimes be wrong, but who else besides other experts – and sometimes the very same experts at a later time, with more data or better methods – gathers the evidence to show where and how experts are wrong?

Moreover, the fact that scientific opinion does change over time is its greatest strength, not a basis for doubting or criticizing any given scientific opinion. It baffles me when people selectively fail to understand this: I have heard more than a few global warming skeptics – even some very bright people – use the argument that climate scientists were predicting the next ice age a few decades ago, and now they’re all talking about global warming, so why should we listen to them now?

Well the first answer to such a doubter is this: You should listen to the climate science experts because they know something about climate modeling and prediction and you know nothing whatsoever about it. I could also point out that the two predictions are not contradictory because they are on completely different time scales: The next ice age is expected to descend some time in the next few thousand years, possibly in the next few hundred, whereas global warming is a current and ongoing trend expected to get much worse over the next few decades. But aside from all that, there is a deeper confusion behind this criticism, and that confusion is worth addressing.

People used to think that the sun moved around the earth. Presumably, even the “skeptics” I’m addressing here look at the change to a heliocentric model of the solar system – a change in scientific opinion – as part of the progress of knowledge. To them, I say this: If you accept that knowledge progresses over time with new evidence and understanding, how can you possibly justify rejecting some particular change in scientific opinion simply because opinion has changed? Even if climate scientists were predicting global cooling thirty years ago and global warming now, don’t you think three decades of advances in measurements and computing power and all that jazz, not to mention three more decades of ongoing climate data, might just make the basis for current scientific opinion a little stronger than the basis for the former opinion? Any argument with this general structure – Experts used to say this, but now they say something else, so why should I believe any of them? – is the most anti-scientific, illogical nonsense imaginable. Such an argument can only be made based on the assumption that changing conclusions based on new evidence is a bad thing!

While it is certainly foolish to place more trust in your own uninformed opinions than in the hard-won knowledge of masses of experts, it is even more foolish to go around thinking that experts changing their minds is a sign that experts shouldn’t be trusted at all. Surely the people whose claims ought not be trusted are those who never change their minds when confronted with new evidence!

Here’s the real crux of the problem: If a given person (1) doesn’t participate in that process of asking and answering important scientific questions, and (2) has not developed the expertise to do so, and (3) has not even bothered to read what the actual experts have to say, then it quite naturally follows that (4) that person’s “skepticism” is not in fact skepticism or critical thinking or anything along those lines – it is pure, unadulterated ignorance.

These self-styled skeptics often reveal this ignorance with the quality of their “criticisms” and “hard questions” they direct at the conclusions they don’t like. For example, take the ever-delightful “If humans evolved from monkeys, why are there still monkeys?” No, please. Take it. I’ve had quite enough of it.

Not all the “skeptical” criticisms are so transparently moronic.”But if temperatures go up, won’t that just cause more evaporation and more clouds, which reflect sunlight?” seems like a plausible sort of question to ask about global warming. But the problem here is that such criticisms are being offered by people who are not themselves experts – who are generally not even vaguely knowledgeable – in the field whose conclusions they are criticizing. Here’s a hint for self-styled doubters: If you can come up with a few “criticisms” or “tough questions” about evolution or global warming or whatever off the top of your head, maybe the thousands of working scientists who’ve spent a significant chunk of their lives developing expertise, gathering data, refining models, and arguing with each other about all of it might just have asked those questions as well – if they’re worth asking. (Do you honestly think climate scientists don’t account for evaporation and cloud reflection in their studies and models? That working biologists are unaware of the existence of monkeys?) Not only have the collected mass of experts probably asked your questions, they probably have a few answers, too. And those answers have led to more detailed and specific questions, which they have also answered, or are continuing to try to answer. And so on.

When whatever opinion you cling to about evolution, or global warming, or whatever other science findings you don’t like is based on near-total ignorance, why should anyone care whether you are convinced or dubious? More importantly, why do you care about your own opinion? Why do you feel entitled to have any kind of firm opinion on scientific theories and facts about which you know nothing whatsoever?

And no, experts don’t always agree. But when you aren’t well-informed enough about a subject to distinguish between a real expert and a two-bit hack with an agenda, then your uninformed choice of which expert opinions to embrace as your own has no more worth than your own uninformed opinion on the matter.

If someone is not in any way engaged in the process of scientific inquiry – not even to the point of reading up on what’s said by science experts who do their valiant best to explain science to the lay public – then that person’s opinion is completely worthless. No, actually, “worthless” is too hasty: Such a person’s opinion does not merely lack value, it actually has negative value. The endless repetition of completely baseless, uninformed opinions is an obstacle to and distraction from the process of inquiry and growth of understanding in any and every field.

The only worse crime against the progress of humanity is to be one of the pseudo-experts who actually have some knowledge in a given area, but use their expertise to generate and spread bad arguments and cheap rhetoric that feed the ignorance of the “skeptical” masses. Take, for example, any and everyone affiliated with the Discovery Institute, or the anthropogenic global warming skeptics discussed here, or Leon Kass (the link is to a recent speech, but his entire career qualifies).

Really, I don’t blame the individual confused, ignorant “skeptics” so much: As I said, rationalization is a part of human nature, and is not easily overcome. But people who have all the tools necessary to overcome rationalization and instead embrace it, who actively choose the path of willful ignorance and lies – and further, devote their life to spreading ignorance and lies – I don’t have the words to express my utter contempt for their character. If there is anything of substance lurking within the vague concept of “human dignity” that Leon Kass is so fond of tossing about, surely his own obscurantist, anti-science, emotional-button-pushing claptrap is amongst the gravest offenses against it.

George M. Felis is a bipedal primate with ill-adapted feet and an over-developed neocortex. He is also a Ph.D. student in philosophy at The University of Georgia whose dissertation attempts to get ethical theory and evolutionary biology talking to one another (despite their often difficult relationship history). Religion and himself are two of the many things he doesn’t take all that seriously. Philosophy and science are two of the several things he does take seriously, at least sometimes.