I’ll just come right out and say it: Every human being is ill. Either we’re clearly sick, or we’re carriers waiting to infect others while our own sickness has yet to manifest.

What is this disease? Well, in layman’s terms it’s called crainus brainus. Essentially that each of us has a brain that doesn’t work nearly as well as we believe.

An excellent case is made in our behavior toward COVID-19. We argue and whine about masks, social distancing and other “silly” science that restricts us from doing what we like.

“Masks just trap bad air inside them.”

“Masks are a government conspiracy against our unalienable rights.”

“Why don’t other animals have to wear masks?”

All of these are based on the sound science of people believing that they know more than they actually do.

Consider human behavior during other pandemics. For example, the bubonic plague. It killed roughly a third of Europe’s population in the 14th century.

Note: I say “roughly” because no one knows for sure how many people died. Calculators hadn’t been invented yet, and most survivors were incapable of adding sums beyond a couple of numbers.

Never mind that. The point is that the Black Death was real and so were the people who perished because of it.

Being a highly superstitious lot back then, many people believed that the plague was divine punishment. God was cursing them for some transgression worthy of killing even those who hadn’t done anything wrong.

If religious history regarding curses has taught us anything about divine punishment, it’s that God has no better aim than your average drive-by shooter.

Another theory considered sound by some back then was that Jews were poisoning the wells. While never proved to be the cause, of course, it did make people feel better — especially while killing Jews.

Same with cats. Someone — almost certainly a cleric — had a brainstorm suggesting that cats were minions of Satan. So, Europe exterminated much of its feline population. The cats got even, though, because it was actually rats that transmitted the disease. In the absence of cats, the rat population exploded, and so did the plague.

But there had to be a cure, right? I mean, even if God is trying to kill you, surely there must be some way of dodging it.

I know! Repentance. Lots of people gave their last bit of wealth to the church. This worked out well for the church but left the now penniless in a lurch. And they continued to die.

Then there were flagellant monks, who traveled to various cities — thus helping spread the disease — and, for a nominal cost, would flog themselves as a way of purifying themselves and anyone else nearby.

Some people moved into sewers believing that the unclean air would prevent the fresh air plague from infecting them. Didn’t work. If the plague didn’t kill them, living in a sewer did.

One of the most outrageous “cures” was shaving the butt of a live chicken and strapping it to the infected person’s swollen lymph nodes. The idea being that the chicken would get sick and draw the illness out of the dying patient. And you thought wearing a mask was annoying.

Other protective measures were carrying packets of herbs, rubbing bits of chopped-up snakes over oneself, bathing in fresh urine, and applying a mixture of resins, flower roots and human excrement.

It’s in the brain, people. We’re so much smarter than other animals that it’s a wonder we’re still around.

Robert Kirby is The Salt Lake Tribune’s humor columnist. Follow Kirby on Facebook.