I was watching the rather hokey Star Trek V last night and one of the comments made by Sybok, who turned out to be Spock's half-brother (in something of a deus ex machina), was that "People used to believe that the earth was flat"; as though that were some sort of proof that we know live in more enlightened times.
Granted that many people did in fact think that the earth was flat and in some cases a disk like object suspended upon the seas, this was in no way universally the case. Plenty of people did not think that the earth was flat; many even took measurements which quite conclusively proved otherwise, even though their calculations and basic assumptions were wrong.
He spreads out the northern skies over empty space;
he suspends the earth over nothing.
He wraps up the waters in his clouds,
yet the clouds do not burst under their weight.
He covers the face of the full moon,
spreading his clouds over it.
He marks out the horizon on the face of the waters
for a boundary between light and darkness.
- Job 27:7-10 (NIV)
There are theories which suggest that the book of Job might be the oldest book in the Tanakh. Job appears in the third section of the Tanakh called the Ketuvim, which include the poetic writings, as well as other assorted leftovers and the two books of Chronicles.
Job was possibly written between 2200-1800BC and if this is the case, then a rather obvious and stark question arises... How could Job have possibly known that the earth hangs over nothing?
Second to this, anyone who has ever stood on the shore of any beach, stood on a very high mountain or even been on a ship in the middle of the ocean, will immediately be struck by the round shape of the horizon; no doubt this is what Job refers to at the end of this little section.
Still further in the book of Isaiah which identifies itself in the 8th Century BC, we find this little nugget:
He sits enthroned above the circle of the earth,
and its people are like grasshoppers.
He stretches out the heavens like a canopy,
and spreads them out like a tent to live in.
- Isaiah 40:22 (NIV)
The word circle in this verse is the Hebrew word "chug" (חוּג). This word is almost exclusively used as the word "circle". I've heard descriptions both arguing in favour of this meaning a globe and a disk and so it perhaps isn't wise to use this as a basis to start an argument as to what the ancients thought. Bear in mind that the Bible itself is more a description of how God relates to people and so if you want to find out what scientists thought, then perhaps it;s best to ask the scientists.
Both Pythagoras who lived in the 6th Century BC and is best known for his theorem relating to triangles and Parmenides a century later, concluded that the Earth is spherical; as did Aristotle and Eratosthenes of Cyrene not only tried to calculate the circumference of the earth but also the angle of the tilt of the Earth.
Aristarchus of Samos even put the sun at the centre of the universe and using trigonometry, thought that the Sun was 18 times further away from the Earth than the Moon is (it actually is about 400 times).
Skip forward many hundreds of years and Columbus who sailed to the new world, didn't leave Spain on the basis that he thought that the world was round when everyone else thought that it was flat, but rather that he thought that the Earth was much smaller than it actually is. Columbus thought that he'd landed in India, despite never having been there before and called the people who lived there "Indians" on that basis.
If anything it might be true that the idea that "People used to believe that the earth was flat", came from a political conflict rather than what people actually believed:
The myth that people in the Middle Ages thought the earth is flat appears to date from the 17th century as part of the campaign by Protestants against Catholic teaching. But it gained currency in the 19th century, thanks to inaccurate histories such as John William Draper's History of the Conflict Between Religion and Science (1874) and Andrew Dickson White's History of the Warfare of Science with Theology in Christendom (1896).
- James Hannam, God's Philosophers: How the Medieval World Laid the Foundations of Modern Science (2009).
All of this leads me to wonder why people think that people thought that the earth was flat but I don't wonder for very long. The truth is that if you ask most people a whole range of questions, they don't really know the answers and more importantly, don't care.
Maybe people think that people thought that the earth was flat because they don't question things enough; that has far more serious implications that the mere shape of the earth.