Instigator / Pro

By the 19th Century, Evidence Already Showed Earth is NOT Flat


The debate is finished. The distribution of the voting points and the winner are presented below.

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After 1 vote and with 6 points ahead, the winner is...

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Two days
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Contender / Con

Pro and Con cannot use any evidence from after the year 1900 MD. I will prove the Earth is NOT flat using only proofs from before 1900, therefore making it impossible to rely on NASA.

Burden of Proof is shared.

Round 1
Con must find evidence to the contrary that these ideas could not have been replicated before 1900.

NPFE = Not possible on flat earth
  • Ships disappear over horizon NPFE (Far-reaching telescope-like lenses were invented before 19th century)
  • Greek mathematician proved with different shadow length at time of year gives 7 degree curve of earth, and approx. circumference. NPFE.
  • Great philosopher Aristotle also argued for the spherical earth, using the following ideas [Aristotle section]: 
  •           Every portion of the Earth tends toward the centre until by compression and convergence they form a sphere.
  •          Travelers going south see southern constellations rise higher above the horizon; and
  •          The shadow of Earth on the Moon during a lunar eclipse is round.
  • Even Medieval scholars: "...unanimously agreed that the Earth is spherical or round".
  • Ferdinand's circumnavigation NPFE.  To add upon this, Sir Francis Drake also successfully circumnavigated.

We can use discoveries after 19th Century began to analyse their evidence's actual capacity to 'show'.

to make something clear or prove something to be true

that which tends to prove or disprove something; ground for belief; proof.
Ships over horizon and all related phemonenon would (or do) occur on a flat plane.
Regardless of Earth's shape, things further away appear to move 'down', the sunnier the day is the closer and/or clearer the horizon appears (think of mirages),

Sources to help illustrate the illusion (first source has an excellent explanation):

Lunar Eclipses merely mean the moon is out of the sun's light-range, it doesn't prove the Earth is in between. Now, I'd like you to consider an eclipse that happened, it shouldn't on a Round Earth. 

To help you envision the physics and shipping routes on a flat Earth as well as Sun/Moon rotations see the following:
Round 2
The rules stipulate that neither debater can use evidence from after 1900 (or events that occurred after 1900 and cannot/were not replicated before such). Con has violated this rule; please deduct conduct points from him and ignore his argument. Con has failed to address any of my proofs. Extend them.

Even if voters buy con's argument, a non-NASA website explains how this occurred, stating "Due to atmospheric refraction, we can also observe the Sun and the Moon even if geometrically they are slightly below the horizon. Atmospheric refraction raises celestial objects close to the horizon upward by about 34 arcminutes or 0.57°. In the case of our lunar eclipse, atmospheric refraction raises the Sun, and the Moon upward by 0.57°. To simplify things, we add it to the figure of the dip of the horizon above." As you can see, con's argument is nonsense.
The rules stipulate that we can't use evidence from after that. However, if we aee to analyse what the evidence from before it shows, we need to be able to analyse it to the fullest extent.

If evidence from before a certain year showed you that a lie was true based on your misinterpretation of exactly what it showed, what then did it actually show you?

This debate is being held in 21st Century, we are analysing evidence from before 20th Century (the title implies before 18th but the word is 'by') to see whether or not it actually showed the Earth is not flat.

I am saying any and all interpretations of what was seen and happened failed to rule out a flat Earth, if people erroneously thought it didn't, thatst due to their ignorance, not due to what rhe evidence actually showed or didn't show.

What Pro is doing is called a red herring fallacy. Even if my evidence were espunged from my Round 1, the rest of the reasoning remains and Pro hasn't answered it. Circumnavigation works regardless.

Round 3
Con says that the ship over horizon and very far things could give the illusion of moving down on a flat plane, but ignores the fact that extremely powerful telescopes would be able to see them -- yet they are unable.

Con thinks the lunar eclipse is impossible but doesn't tell us exactly how it's impossible, or how it counters Aristotle's reasoning or the atmospheric refraction explaining the strange sun-and-moon appearance.

Con also ignores Eratosthenes' proof, perhaps the strongest evidence because it also measures the circumference in addition to proving the roundness (NPFE)

Con claims that the circumnavigation process would still be possible under the flat earth assumptions, but even sailors in modern day would still use similar routes as details in the past (except slightly improved) in order to complete the circumnavigation. The extended length of navigation merely by going a few kilometers to the south means that the radius would be unacceptably massive, extending the circumnavigation by days, weeks, or even months! (Example image)
Evidence that Pro says proved (or 'showed') the Earth was flat:

  1. Things merge into the horizon and appear to go over it, espeically noticed with ancient ships.
  2. Ships also proved that if you keep sailing in one direction you go around the equator (or some equivalent axis to it more north of it) so there appeared to therefore be no edge and if we presumed the South to be identical to the North (since only the North was where full circumnavigation occured), it would lead one to presume a globe.
  3. Greek scientists and mathematicians hypthesised that certain angles of shadow implied curvature (this is identical in reasoning to point 1 and requires one to assume that Earth's curvature is at play, not simple refraction and perceptive illusions).
To counter the second, I provided a couple of images to help you envision both how the sun and moon work on a flat Earth and how circumnavigation is just as viable in the North as in a globe (even same proportions).

The rest I explained were illusions.