This is an excerpt from an article George Orwell wrote in 1946. I will let the text speak for itself.

    Somewhere or other — I think it is in the preface to saint Joan — Bernard Shaw remarks that we are more gullible and superstitious today than we were in the Middle Ages, and as an example of modern credulity he cites the widespread belief that the earth is round. The average man, says Shaw, can advance not a single reason for thinking that the earth is round. He merely swallows this theory because there is something about it that appeals to the twentieth-century mentality.

    Now, Shaw is exaggerating, but there is something in what he says, and the question is worth following up, for the sake of the light it throws on modern knowledge. Just why do we believe that the earth is round? I am not speaking of the few thousand astronomers, geographers and so forth who could give ocular proof, or have a theoretical knowledge of the proof, but of the ordinary newspaper-reading citizen, such as you or me.

    As for the Flat Earth theory, I believe I could refute it. If you stand by the seashore on a clear day, you can see the masts and funnels of invisible ships passing along the horizon. This phenomenon can only be explained by assuming that the earth's surface is curved. But it does not follow that the earth is spherical. Imagine another theory called the Oval Earth theory, which claims that the earth is shaped like an egg. What can I say against it?

    Against the Oval Earth man, the first card I can play is the analogy of the sun and moon. The Oval Earth man promptly answers that I don't know, by my own observation, that those bodies are spherical. I only know that they are round, and they may perfectly well be flat discs. I have no answer to that one. Besides, he goes on, what reason have I for thinking that the earth must be the same shape as the sun and moon? I can't answer that one either.

    My second card is the earth's shadow: When cast on the moon during eclipses, it appears to be the shadow of a round object. But how do I know, demands the Oval Earth man, that eclipses of the moon are caused by the shadow of the earth? The answer is that I don't know, but have taken this piece of information blindly from newspaper articles and science booklets.

    Defeated in the minor exchanges, I now play my queen of trumps: the opinion of the experts. The Astronomer Royal, who ought to know, tells me that the earth is round. The Oval Earth man covers the queen with his king. Have I tested the Astronomer Royal's statement, and would I even know a way of testing it? Here I bring out my ace. Yes, I do know one test. The astronomers can foretell eclipses, and this suggests that their opinions about the solar system are pretty sound. I am, to my delight, justified in accepting their say-so about the shape of the earth.

    If the Oval Earth man answers — what I believe is true — that the ancient Egyptians, who thought the sun goes round the earth, could also predict eclipses, then bang goes my ace. I have only one card left: navigation. People can sail ship round the world, and reach the places they aim at, by calculations which assume that the earth is spherical. I believe that finishes the Oval Earth man, though even then he may possibly have some kind of counter.

    It will be seen that my reasons for thinking that the earth is round are rather precarious ones. Yet this is an exceptionally elementary piece of information. On most other questions I should have to fall back on the expert much earlier, and would be less able to test his pronouncements. And much the greater part of our knowledge is at this level. It does not rest on reasoning or on experiment, but on authority. And how can it be otherwise, when the range of knowledge is so vast that the expert himself is an ignoramus as soon as he strays away from his own specialty? Most people, if asked to prove that the earth is round, would not even bother to produce the rather weak arguments I have outlined above. They would start off by saying that "everyone knows" the earth to be round, and if pressed further, would become angry. In a way Shaw is right. This is a credulous age, and the burden of knowledge which we now have to carry is partly responsible.


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According to Wikipedia, the equatorial diameter of Earth is about 43 km greater than its polar diameter.

Oval? You decide.

the ancient Egyptians, who thought the sun goes round the earth, could also predict eclipses

That the sun goes round the earth is not more or less right than the converse. It's a construction of the same system in different coordinates and quite valid.

However, the Oval Earth theory is wrong, and you can't predict eclipses from it correctly.

More to the point, arguments like this against knowledge from authority rely on implicitly accepting most such knowledge, and only disputing a few choice examples. In Orwell's story, how do you know about the ancient Egyptians, or what theories the Lord Astronomer espouses, if not from "newspapers and science booklets"? How do you know what astronomical knowledge exists regarding navigation or eclipses? How can you know when eclipses occurred before your birth (to work out cycles)?

If you don't accept the commonly held theories (because you haven't verified them yourself), why should you accept the commonly known facts (without having observed all of them yourself)?

I also don't agree with Orwell that Round Earth theory is "exceptionally elementary information". It really doesn't directly influence the life of the average person in any way; we don't normally make decisions predicated on the truth of that theory outside of a few professions. It's just a very well-known piece of common knowledge, in part because some Flat Earthers still exist who deny it, and due to the related Flat Earth Myth about the Dark Ages.

Relying on expert knowledge is a good way to evaluate claims only the first few times we encounter them. If we act on a piece of knowledge repeatedly, this should allow us to directly confirm or disconfirm it. If this doesn't happen, it's probably a sign that the purported knowledge or theory is just a marker in a political/social/religious game. We know Oval Worlders are the enemy and so our authority figures always affirm the Round World theory, but this doesn't have anything to do with the actual shape of the earth.

That the sun goes round the earth is not more or less right than the converse. It's a construction of the same system in different coordinates and quite valid.

Not if you take "the sun goes round the earth" to be an explanation for the sun's apparent movement in the sky.

It's not as if the Earth goes around the sun. The earth is in an orbit around the center of the galaxy and the sun interferes with it making it do so in a curly manner. You sol-centric people are small minded!

The sun does go round the earth, and it's a perfect explanation/prediction of its movement in our sky. If you plot the point on Earth's surface above which the Sun is located, it goes round and round the planet (with seasonal perturbations).

The only problem with this theory (things go round the Earth) is that it doesn't explain the movement of bodies other than Sun and Moon. Retrograde motion leads you to epicycles, which are hard - you never have quite enough of them. That's why "things go round the Sun" is much better, at lest until you discover extrasolar objects aren't immobile.

But as far as the Sun-Earth system is concerned, both theories are equally valid.

Er, actually, of course, "things go round the Sun" doesn't correctly explain day and night. The correct theory is that the Earth turns on its axis, and goes round the sun but much more slowly. That's why the unified theory of "sun going round the earth" is much simpler and more elegant to start with.

Conventional wisdom is a good heuristic. We tend to focus on the cases where it was wrong (the Earth is flat, the Earth is the center of the universe) more so than when the CW is correct. It's great to question/reaffirm widely held beliefs but my attention is a precious resource.

Think about it: specialized communities spring up for times when the collective wisdom of humans is wrong, not when it's right.

It is conventional wisdom that the conventional wisdom in the Middle Ages was that the world was flat. Your conclusion is right for the wrong reason.

Irrelevant to your point, but the earth is oval shaped

"The difference between the longest and shortest diameters is 44 kilometers (27 miles), and that means that the "oblateness" of the earth (its departure from true sphericity) is 44/12755, or 0.0034. This amounts to l/3 of 1 percent.

To put it another way, on a flat surface, curvature is 0 per mile everywhere. On the earth's spherical surface, curvature is 0.000126 per mile everywhere (or 8 inches per mile). On the earth's oblate spheroidal surface, the curvature varies from 7.973 inches to the mile to 8.027 inches to the mile.


Even the oblate-spheroidal notion of the earth is wrong, strictly speaking. In 1958, when the satellite Vanguard I was put into orbit about the earth, it was able to measure the local gravitational pull of the earth--and therefore its shape--with unprecedented precision. It turned out that the equatorial bulge south of the equator was slightly bulgier than the bulge north of the equator, and that the South Pole sea level was slightly nearer the center of the earth than the North Pole sea level was."

Isaac Asimov

(ironic that this excellent article should have a secondary use as a reference for the example it discusses!)

I can't think of a single conclusive piece of evidence - but thinking the earth is NOT round would require conspiracy thinking sufficient to make the "we never landed on the moon" nuts and homeopathists look rational.

Here are 3 to start:

1) Maps work in long range air and marine navigation

2) Satellite orbital information

3) Theory of gravitational "rounding" (I can't remember the correct technical name off-hand).

Remember, this was written in 1946, well before space exploration began.

I've always found the various pictures and movies of Earth from space to be pretty convincing as well.

Have you actually employed any of this? Surely there could be an alternate explanation for the satellites. And I'd say your average man-on-the-street probably wouldn't need an entire conspiracy to think the Earth is actually round. Or flat. Or some other shape that it isn't.

As someone who works at a company that makes satellite receivers and processes huge amounts of incoming satellite data every day... and actually uses the Earth's major and minor axes in calculations every day... I'd like to hear your alternate explanation :-)

That said, I can (though with some difficulty) imagine conspiracies or honest errors afflicting other textbook facts, like the precise distance to the Sun.

As someone who works at a company that makes satellite receivers and processes huge amounts of incoming satellite data every day... and actually uses the Earth's major and minor axes in calculations every day... I'd like to hear your alternate explanation :-)

I was more speaking of the average sort of person, who's barely literate and works with their hands. It depends entirely on what sort of direct evidence the person's been exposed to. If it's merely that GPS works or that their TV uses satellites, there could be a myriad different explanations of how these things work that would probably sound less like gibberish than the real one.

Except for studying marine navigation in my live on boat/ocean settlement phase back in my teens and twenties, no. But I was more suggesting that there are thousands of people (possibly millions) - pilots, navigators, amateur astronomers - who regularly use the first two. If they were off even a little, lots of somebodies would have noticed and they would have been corrected for the proper shape of the earth.

Each individual human knows very little compared to the system that comprises humanity. You are a neuron in a vast, globe-spanning brain.

I'm not sure I know what it means to say that the system "knows" things. We often speak as if evolution or genes "want" things, but everyone knows that it's only a metaphor. When you speak of the global brain, do you mean it strictly as metaphor, or are you saying something more?

I'm not sure I know what it means to say that humans "know" things. We often speak as if humans "want" things, but everyone knows that it's only a metaphor.

Yeah, yeah, very cute. I agree that folk psychology has a few problems with it, but I'm not yet ready to toss commonsense notions like knowing and wanting entirely out the window.

Okay, think of it this way: we can see why natural selection would result in organisms with a folk psychology of selves that have beliefs and desires, even if these abstractions are a little leakier than we think they are. But human societies haven't faced the same kind of selection pressure that could produce such adaptations, so whatever sense human societies can be said to know things, it's probably very different from the sense in which individual humans can be said to know things.

Evolution is no longer the only optimization process in this world - human societies don't need to undergo evolution, they are intelligently designed. If you think human societies don't develop a sense of self, just wait for the next July 4, or whatever your local day of nationalistic celebration is.

To say that a society has a sense of itself seems absurd; societies are not sensing things. How would you distinguish between a society that has a sense of itself versus one that doesn't? By the behaviour and identity of its members? That makes as much sense as determining if I have a sense of self by surveying my neurons to see if they identify as being a part of me. A group of sensing beings ascribing to an ideology does not a new entity with a sense of self or a capacity for knowledge make.