Many people who advocate for science and scientific thinking try to dismiss their opponents as stupid. In a discussion I was having with someone on Facebook today, the OP posted a meme that went something like “If people don’t believe in vaccines, climate change or evolution, why do they believe scientists when they predict eclipses?” The implied answer is essentially that they’re mentally impaired and that we should make fun of them.
The above pic is of a real life vaccine researcher named Jacinto Convit. I think he looks like a supervillain lol. Image credit alexantonovici on Imgur
The real answer is that it's because of the nature of the various different kinds of science mentioned here. There are a lot more uncertainties involved in say, vaccines, as opposed to planetary motions. People are told "there's going to be an eclipse tomorrow at such and such time" and that happens every time, exactly as predicted, with no failures that I've ever been made aware of. There are probably minuscule timing errors, but nothing that your average layman would care about. With vaccines however, people are told "vaccines are safe and will keep you from getting sick," and then they're shown by some conspiracy theorist several examples of rare instances (but real ones) of people being killed by vaccines. This leads them to believe that they're being lied to, and that vaccines in fact do more harm than good. This is still an error in judgement because they haven't considered what the statistics on vaccines tell us, but it's not quite the same as "happens exactly as predicted every time," and so it's a lot harder for people to wrap their heads around.
There are also examples of the way in which vaccines are typically administered by medical professionals that haven't been properly reviewed for safety, further calling into question the credibility of the scientists in the eyes of conspiracy theorists. This is discussed thoroughly in the book The Vaccine Friendly Plan by Paul Thomas, M.D. and Jennifer Margulis. To very briefly sum up what they’re saying in this book is that aluminum, a metal used in vaccines to help stimulate an immune response, may be neurotoxic at the levels injected into children’s tiny bodies when multiple vaccines are administered at once. No safety studies have been conducted at those levels, only at the single vaccine dose level. So, in order to be better safe than sorry, I’m following their recommendations to space out the vaccines with my children. There are also other side-effects of many of the recommended vaccines that can be avoided by simply waiting until those vaccines are relevant to the child’s life situation. I am also following this recommendation. In spite of these revelations, the scientific and medical community has made almost no effort to investigate further or change their practices and recommendations. Then they wonder why people mistrust them and throw the baby out with the bath water, and they go on dismissing their opponents as idiots. There are similar problems with climate science and evolution.
I think the dismissiveness of the Facebook post paraphrased above perfectly mirrors the attitude of the scientific community in general toward the public on these issues. I also think this is part of the problem, and definitely not the solution. If people don't understand or trust the science, it's because the scientists have done a poor job of explaining it to them, not because most people are too stupid to understand at least the basic principles. Writing these people off as if they're mentally impaired isn't going to win any converts, and will only serve to reinforce their rejection of the information.
This is not to mention the erroneous belief systems of people with high IQ's. I mean, universities are filled with Marxist professors, and that has to be one of the most dangerous ideologies man has ever devised. Marxists killed over a hundred million people in the twentieth century, and yet some of the most intelligent among us still think Marxism is a great idea. This is all the evidence you need to determine that erroneous belief systems don't have their origins in stupidity. Suffice it to say, that if rather than appeal to the intellect of your fellow human beings by making good arguments, you find yourself shouting them down and telling them they're stupid, you might want to take a look in the mirror and figure out what you're doing wrong, and try again.