You might have seen this before. The line on the bottom looks longer than the line on the top. You know it isn’t, but even if you already know, even if you measure the lines yourself and confirm that they are the same, you keep seeing them as different lengths.

My glasses have a custom lens to correct for my personal sight problem. But when I look at this optical illusion, I still misinterpret what I see, just like everyone else. This is because illusions don’t happen in our eyes, they happen in our brains. They are systematic misinterpretations, unrelated to individual sight problems. Knowing that most people are deluded means you don’t need to be embarrassed. Instead you can be curious: how does the illusion work?

Similarly, you can look at the results from the public polls and skip being embarrassed. Instead be curious. How does this “global illusion” work? Why do so many people’s brains systematically misinterpret the state of the world?

This is what the author tries to tell us. There are many reasons that we see the world wrongly and even if shown proof we still continue to see it that way.