@jammin3000 said in #1:
> probably socrates was flatearther himself but what would he say about them if he lived now?
What makes you say that? It's unlikely that Socrates (c. 470 – 399 BC) believed the Earth to be flat.
He lived in the 5th century BC. By then the spherical shape of the Earth was already a well-established fact among the Greek intelligentsia according to "Early Greek Astronomy to Aristotle"; Dicks, D. R., Cornell University Press (1970), p.68.
It is uncertain who was the first to posit a spherical Earth but it's very likely that whoever it may have been lived prior to (or at the very least contemporaneously with) Socrates:
In the pre-socratic philosophy of Thales of Miletus (c. 626/623 – c. 548/545 BC) the Earth "rests on water". Perhaps this thought was motivated by the presence of fish fossils on land (roughly 2500 prior to the idea of plate tectonics this finding would for sure be puzzling I imagine), we simply don't know. While not a direct statement on the shape of the Earth this may perhaps be interpreted as a belief in a flat Earth resting on some medium.
One student of Thales was Anaximander (c. 610 – c. 546 BC) who later became the second master of the Ionian school of philosophy. Unlike his teacher he rejected the notion that the Earth needed a medium to rest upon and instead posited a free-floating Earth which he thought to be a cylinder with a height one-third of its diameter:
"Whereas Thales thought the Earth floated in the great Ocean, Anaximander saw the Earth as floating in the infinite. Where Thales conceived of things falling down to Earth, and Earth being above the Ocean, Anaximander saw the Earth as the centre, and that things could fall from any direction."
en.wikipedia.org/wiki/Anaximander#A_free-floating_EarthThis conception has been regarded as "one of the boldest, most revolutionary, and most portentous ideas in the whole history of human thinking." by philosopher of science Karl Popper (1902 – 1994).
Anaximander may have been wrong about the precise shape of the Earth but not very wrong. Notice that he chose a shape – namely the cylinder – that includes a circle which was likely motivated by the observation that the shadow cast by Earth on the moon during a lunar eclipse is always circular.
Anaximander was an overall fascinating philosopher: in the 7th and 6th centuries BC he believed in the plurality of worlds and speculated about a natural origin of mankind (from aquatic beginnings)! He also thought the sun to be massive and distant.
Next we have Pythagoras of Samos (c. 570 – c. 495 BC) and Parmenides of Elea (c. late 6th century BC – 5th century BC), both of whom have been credited with being the first to have conceived of a spherical Earth:
en.wikipedia.org/wiki/Pythagoras#In_astronomyUnfortunately both philosopher's thoughts have only partially been recorded for posterity (and preserved), so we are left with mere fragments (the same applies to all of the aforementioned philosophers). The specific reasoning that may have lead them to a spherical shape of the Earth is unknown as far as I know. I imagine it must have been similar to the reasoning Aristotle (384–322 BC) gave 150 years later (in c. 350 BC) in his treatise "On the Heavens (Greek: Περὶ οὐρανοῦ)" in which he argued for Earth's sphericity as follows:
1) Everything with mass seeks and moves towards "the centre of the whole [universe]" and does so equally from all directions. This universal law applies to a "clod or common fragment of the earth" as it does to the Earth (as a massive body) itself. Whether Earth was formed that way or not, it must therefore surely be at the centre of the universe (by now) and spherical (ab initio or due to its natural tendency to arrange itself equally around the centre).
2) "[...] [I]n eclipses the outline [of the shadow] is always curved: and, since it is the interposition of the earth that makes the eclipse, the form of this line will be caused by the form of the earth's surface, which is therefore spherical."
3) "[...] [S]ome stars [are] seen in Egypt [...] which are not seen in the northerly regions; and stars, which in the north are never beyond the range of observation, in those regions rise and set. All of which goes to show not only that the earth is circular in shape, but also that it is a sphere of no great size: for otherwise the effect of so slight a change of place would not be quickly apparent."
http://classics.mit.edu/Aristotle/heavens.2.ii.html (On the Heavens, Book II, Part 14)
It seems clear that both Pythagoras and Parmenides were already aware of at least one of the observations 2) and 3) in the 6th and 5th century BC and that this motivated their view that the Earth is a sphere. And by extension it is very likely that Socrates knew that the Earth was a sphere in the late 5th century. Of course we cannot be entirely sure but I'd say Socrates was no slouch ;-)
