Did Eratosthenes accidentally prove FE?

Hi
What was wrong with his sticks experiment?
It obviously doesn't prove we live on a globe but I was wondering if it proves FE.

Eratosthenes never set out to prove that the earth is round, because it was already known to be round.  He set out to determine the circumference of the round earth, which he did with remarkable accuracy given the tools that he had available at the time.

That's alot of crap.

The previous guys? They presented it as philosophy.

As for Eratosthenes? When you base latitude and longitude on Eratosthenes' own formulas, of course it is remarkably accurate today.

That's right Eratosthenes is credited with inventing longitude and latitude. Can you say conflict of interest?

Where's the conflict?  Seems to me that the two complement each other.

No, they kinda don't.

Suppose I go around declaring that nearly every cat I meet needs feline acupuncture. I also establish the medical field of feline acupuncture.

When the same idea you promote is part of what you introduce, that is conflict of interest. That is literally like me going on this forum, talking about the Bible then saying "Hey also? Buy my Bible." Just as it's not cool to suddenly raise the font size of a link, right?

So no. Totally not cool that his experiment is in order to tell us about longitude and latitude. Which in turn uses latitude and longitude in circular reasoning to prove the theory is correct.

Methinks he is trying to sell maps. Sure enough, here's his map.

Amazingly accurate!

Bullshit. I call bullshit.

What was wrong with his sticks experiment? It obviously doesn't prove we live on a globe but I was wondering if it proves FE.

Nopadon, the issue with Eratosthenes’ sticks experiment isn't about whether he could measure shadows—it's about the A Priori Assumption he used to interpret those shadows. This is where most people get lost in the "remarkably accurate" noise.

The experiment is a perfect example of Underdetermination of Theory by Evidence. You have one set of data (shadow lengths at two different locations) and two completely different geometric interpretations:

Globe Interpretation: Assume the Sun is 93 million miles away (parallel rays). Therefore, the shadows diverge because the ground is curved.

Flat Plane Interpretation: Assume the Earth is flat. Therefore, the shadows diverge because the Sun is Small and Local.

h = d / tan(θ)

If you use the flat model, the math is perfectly consistent. The angles don't prove a curve; they simply prove that the Sun is at a finite distance. The "conflict" isn't about selling maps or inventing longitude; it's about Circular Reasoning. If you assume the rays are parallel (93M miles away), you "calculate" a circumference. If you assume the ground is flat, you "calculate" the Sun’s height (roughly 3,000 miles).

The experiment doesn't "prove" either model on its own; it simply confirms the geometry of whichever model you already decided to believe in.

To claim it proves a globe is a logical fallacy known as Affirming the Consequent. It’s like seeing a wet street and concluding it rained, ignoring the fact that a sprinkler could have caused it. Eratosthenes didn't "find" the curve; he assumed it and then measured the result of his own assumption.

The "Remarkable Accuracy" is just a result of consistent trigonometry applied to a flawed premise. Whether he was "selling maps" or not is irrelevant; the Optics tell us that localized shadows are a hallmark of a local light source, not a distant giant.

That was what I was trying to get at.

The conflict of interest creates and is because of circular reasoning. In fact, this is probably the most "round" thing about their theory.

When the same idea you promote is part of what you introduce, that is conflict of interest. That is literally like me going on this forum, talking about the Bible then saying "Hey also? Buy my Bible."

No, he was using latitude and longitude and the shadow experiment to refine the round earth model at the time.

So no. Totally not cool that his experiment is in order to tell us about longitude and latitude.

The experiment was about the circumference of the earth, not longitude and latitude.

Methinks he is trying to sell maps. Sure enough, here's his map.

Amazingly accurate!

You say that like selling accurate maps is a bad thing.

Next thing you know, you're going to say that Thomas Edison had a conflict of interest by finding out what people wanted to make their lives better and then inventing and selling things to make people's lives better.

Are you blind?

Does that map look at all accurate?

Libya is enormous, Russia and Cyberia (pfft) are weirdly shaped and sized, and there are imaginary islands like Taprobane.

Selling crackpot maps is against the standards of safety for people who use them to get around at sea, and I'm reporting him to the Better Business Bureau for fraudulent products.

The experiment was about the circumference of the earth, not longitude and latitude.

The circumference is using measurements extrapolated from the radius, which in turn is extrapolated from assumptions made about total angles. If any of these assumptions are faulty, they mean the measurements in turn have a foundation that is a faulty premise. In much the same way is if in a courtroom, I made an assumption that someone was raped because they had bloody clothing without having been there or witnessed anything. It could also be an unusually heavy period. Without correct premises, you got nothing.

Are you blind?

Does that map look at all accurate?

It's probably more accurate than most of the maps of the time.

Quote

The experiment was about the circumference of the earth, not longitude and latitude.

The circumference is using measurements extrapolated from the radius, which in turn is extrapolated from assumptions made about total angles.

I'm guessing that he was assuming 360 total degrees in a circle and that 7 degrees is about 1/51 of that circle.  Those sound like fairly safe assumptions to me.

It's probably more accurate than most of the maps of the time.

Stupid argument.

Sumerian etchings were better at the time cave art in Europe.


What do you think. Accurate to the real world?

I'm guessing that he was assuming 360 total degrees in a circle and that 7 degrees is about 1/51 of that circle.

You're still missing the point. If he came up with the 7 degree difference because he invented latitude and longitude, there was not proof that there was at any point a difference in latitude. Just a solar noon difference from what he expected.

Flowers bloom because pixies paint them colors. I have found that flowers tend to bloom during and after the vernal equinox. Therefore, pixies come out of hibernation during the vernal equinox (and I have of course definitely proven the initial premise that flowers bloom because of pixies).

He started with the assumption there should be a difference to test in the first place, based on latitude and longitude (which he discovered/invented).  There should be no reason that he tested any of this, except that he was trying to sell maps with his idea.