It seems that I have been lied to by thousands of scientists, educators, and government officials.

At least that is what a group of Coloradans who met in Fort Collins last month believe. They are some of possibly thousands of Americans who contend that the world is really flat, not a globe like my first-grade teacher told me or what I heard from astronauts  as they circled the earth or what I saw in the pictures they took that showed only one side of the Earth.

The flat-Earth believers — who will hold an international conference in November — don’t all see things the same way, but they all believe the Earth is flat. They claim that those of us who don’t believe as they do have been duped by, as you might guess, a massive conspiracy to hide the truth. The belief that Earth is a globe is propaganda, they say, produced by a huge conspiracy of — you guessed it — elite scientists who profit by keeping us all from the truth. They can’t say just how and why the elitists will profit, but that’s what they think. Some say the conspirators use Photoshop to make the earth round in the pictures taken from space, and have rigged GPS devices to fool pilots into thinking they are flying in circles when they are really traveling in straight lines.

Apparently, these people aren’t pretending; they are simply true believers in a pancake-shaped Earth. Personally, I think they are not only out in left field, they are clear out of the stadium. The whole idea of such a massive conspiracy is crazy. If it were true, it must have originated around 2,000 years ago with the ancient Greek philosopher Ptolemy. He had the mistaken idea that the sun revolved around the earth, but he knew Earth was a ball even back then. Surely some of those elitists who have kept the conspiracy alive for 20 centuries would have had too many beers at some point and spilled the beans about the conspiracy, but none have. As for the “Photoshopped pictures” from space, they started appearing in the 1960s, about 20 years before Photoshop was invented in 1986.

I’m not sure which is more unbelievable: the concept of a flat Earth or a conspiracy that would have to have millions of people involved has managed to survive since Caesar Augustus ruled Rome. I believe Ptolemy and my first-grade teacher and I will see some proof next week. I plan to observe an eclipse of the sun next week — something be impossible according to the flat-Earth crowd.

This seemingly sudden attention to the flat-Earth believers is an example of what seems to be an epidemic these days. Many Americans have decided they can’t trust the experts any more, so they simply reject anything that differs from what they believe. That’s why so many reject the notion that human beings are causing climate change, despite the fact that nearly all climatologists offer evidence that it is true. It’s also why many parents refuse to follow their doctors’ advice and to have their children vaccinated, because they fear it will lead to autism, even though there is no evidence that it will. And no matter how many people who have studied Islam or long lived and worked with Muslims tell us that all Muslims are not terrorists, too many Americans still believe they are.

Unfortunately, our president is among those Americans; in fact, that’s quite likely one reason he was elected. He has expressed support for the idea that vaccines cause autism, for example, and he insists that all Muslims represent a danger.

The president bases his actions on what he wants to believe. He can’t believe that he lost the popular vote, so he has begun a major investigation to prove that some 2.5 million fraudulent votes were cast in the 2016 election. There is no proof of any fraud in the election at all and the state officials that run elections — most of them Republicans — reject the idea. Common sense would tell you that 2.5 million fraudulent voters would be impossible to hide, and if there were fraudulent voters, they are as likely to have been cast for the president’s opponent as him. He doesn’t want to believe he didn’t win the popular vote, though, so he has started the investigation.

Now I’m a skeptic, and I’m not averse to questioning authority. In fact, I think we should question authority more often, especially when it comes to government decision making. Experts in any field make mistakes and they can be improperly influenced when they make recommendations about the issues our government deals with.

But it’s a mistake to discount concepts that have been developed through the observations of thousands of scientists over many centuries because you don’t understand them or because they don’t match the way you think the universe should be; that’s what the flat-Earth people do.

Nor is it useful to invent an impossibly complicated conspiracy to explain why something you believe is true; that’s what those who claim voter fraud in 2016 do.

Sound thinking is important. We live in a complex society and a complicated world, and right now that world is facing considerable turmoil. In this situation, making sound decisions is necessary, and sound decisions depend on sound thinking. Fighting with imaginary conspiracies and ignoring science are not the path to sound thinking, even if you are the president of the U.S.