When I look at the sun setting, I don’t think the sun is actually moving; although, from my point of reference it may look that way. But knowing that Earth revolves around the sun and that the Earth, itself, rotates, I’ve long-since conditioned my mind to reason that when I see the sun setting, I’m seeing my little section of the Earth rotate into it’s own shadow.

It’s easy to understand in hindsight. I don’t blame the ancients for getting it wrong, but once the mechanism is understood, it sure is a lot easier to understand things like seasons and shorter or longer periods of daylight (the angle of the Earth to the sun), eclipses (bodies entering shadows cast by other bodies), and the movement of other planets (each revolves at a specific speed, and when Earth ‘passes’ the other planet, it looks like that planet is moving backwards in the night sky).

The ancients had all sorts of explanations for all of this, but they were just claptrap. Actually, some Chinese and Greeks figured it out millennia ago, but the common wisdom remained, by definition, more popular.

What continues to bother me though is that the ancients thought the world was flat. I know this is not true. The evidence for it not being flat was all over the place. I can buy that very few people had any idea how large of a ball we were on. (Columbus’s big idea wasn’t that the world was round, but that the round world was much smaller than commonly thought. He was terribly wrong in his calculations, assuming that when he landed in the Caribbean he was actually in India. Hence West Indies. Hence Indians.) But that anyone other than some backwater hermit thought that the world was flat was just not paying attention to anything.

Scientifically, it was easy to prove with shadows. The Greek, Eratosthenes, took measurements of two pillars and their shadows at known times in two different parts of the world. Using a new field of mathematics called Trigonometry, he computed the circumference of the world. Circumference, by the way, implies roundness.

The ancient world was dominated by trade and conquest. Much of this trade and conquest moved over huge portions of land or sea. Any explorer knew that the edge of the world was just an illusion. There was always something waiting over the horizon. Anecdotally, everyone knew the world was round.

By example, they knew the Earth was round. By looking at the phases of the moon, anyone can clearly see it’s a sphere, not a circle. If one were to take a flat plate, and try to mimic the phases with a light source, he would be disappointed as there would be no shadow until the light source moved completely behind the plate. It takes a sphere to produce those shadows. And the ancients, watchers of the sky, would have seen the shadow of the Earth cast in its own sky creeping along in twilight until it enveloped the heavens. That creeping shadow implies a curved edge, not the hard edge of a flat plate.

We can still see that shadow, on clear nights, but it’s difficult to notice, and, by the time I think of it, it’s already nightfall.

The evidence was all over the place. The ancients knew the world wasn’t flat. Why do we think they did?

I think of this when I hear people talk about what is commonly known, what everyone believes. How can millions of individuals know something, but it will invariably come out wrong when everyone believes it’s opposite? The world wasn’t flat, no one believed that it was, but somehow everyone thought it was flat. The political and social world of today is filled with this magical thinking. No one I know believes any of it. And yet everyone believes it.

The way to end this is to stop–not only to stop believing in the common wisdom, but to also stop believing there is a common wisdom. The people selling it are people who are selling us things that we wouldn’t buy unless we thought our peers were buying it too. This is in all things, physical and intangible. Consider that any idea that everyone believes is not to be trusted, look for it’s faults, break it into smaller pieces, and form your own opinion. In this time of the fractured media landscape, the remaining gatekeepers are desperate and determined to hold onto any group of believers that they manufacture. We don’t have to assist them by aligning with them.