The Ancient Greeks

Championed by Aristotle, the the theory of a Round Earth began in antiquity, contradicting the prevailing belief of a Flat Earth. Aristotle founded his theory on three proofs, which are still in use today as evidence for the rotundity of the Earth. As Greek and Roman influence and culture spread throughout the ages the concept of a Round Earth represented the bastion of classical antiquity, overthrowing ancient knowledge and establishing itself as the cornerstone of Western civilization.

Aristotle's Round Earth Proofs

There are three proofs Aristotle gave for the supposed rotundity of the earth. They are:

• Ships Appear to Sink as They Recede past the Horizon
• The Shadow on the Moon During a Lunar Eclipse Is Round
• The Southern Constellations of the Night Sky Appear to Rise as You Travel Southwards

Eratosthenes' Shadow Experiment

Eratosthenes is famed for his shadow experiment where he determined the circumference of the Round Earth and the distance to the sun. However, this experiment assumes that the earth is a globe and that the sun is far away. The experiment can also be interpreted under a Flat Earth model as well. See:

• Eratosthenes on Diameter
  
• Distance to the Sun

Continuous Universe

The Ancient Greeks believed in a Continuous Universe. This Ancient Greek concept of a perfect universe assumes the following:

• That perfect circles can exist
• That one could zoom into a circle forever and see a curve
• That any length of space can be divided into infinitely smaller parts
• That the space can be infinitely long
• Time can likewise be infinitely divided, or infinitely long
• Light rays travel in perfectly straight lines into infinity
• The Perspective Lines receded infinitely and continuously into the distance

Quotes

  “ Although we condemn flat-Earth thinking as an example of foolish ignorance, a spherical Earth is actually counterintuitive. It’s such a radical idea that it has been ‘discovered’ only once, in Athens after 400 BCE. The concept of the Earth being round didn’t appear in any other civilisation. India and the Islamic world learnt it from the Greeks, while China had to wait until the Jesuits arrived in the 16th century and turned the Chinese view of the Universe upside down. ”
                  —Historian of science Dr.James Hannam (bio), author of "God’s Philosophers: How the Medieval World Laid the Foundations of Modern Science" (Source)

  “ In the past scientists did not use the scientific method we use today. For example, Aristotle was a great thinker in ancient Greece. He carefully observed and tried to check things for himself. But he also wrote things down that had not been proven by the kind of careful experiments scientists complete today. Sometimes Aristotle was wrong. But his work was so respected in Europe that 1,000 years later few people doubted what he had written. Until the 1500's university students were not supposed to question what Aristotle and other ancient thinkers had written. They were just supposed to memorize it. Experimenting and checking things were simply not done. ”
                  —Suzane Glass, Analyze This!: Understanding the Scientific Method

  “ Bacon applied the empirical method of Ibn al-Haytham (Alhazen) to observations in texts attributed to Aristotle. Bacon discovered the importance of empirical testing when the results he obtained were different than those that would have been predicted by Aristotle.[7][8] (Aristotle had never performed experiments to verify his explanations of his observations of nature; in ancient times, constructing an artificial situation was not considered a valid way to discover the laws of nature.) ”
                  —Wikipedia article on Roger Bacon, Father of the Scientific Method

  “ So Aristotle might have been all the more ignorant of the deeper secrets of nature. And wise men are now ignorant of many things which the common crowd of students will understand in the future. ”
                  —Roger Bacon, De mirabile potestate artis et naturae

  “ From 400 BC, with Aristotle, and until the mid-19th century (1830–1850 AD), many scientists have claimed that some organisms can be generated spontaneously from non-living matter, citing larvae as an example and the flies that are generated on decomposing meat. Aristotle had observed the correlation between the rotting of meat, the appearing of larvae on it and the developing of flies. Upon his repeated observations, he found a correlation that developed in a theory (the theory of spontaneous generation). This theory proved wrong (the ‘rotting meat error’ in our story) because it grew out of correlations ‘statistically’ (very) significant but those correlations were wrong ones. Yet, for a long time the theory was constantly applied as ‘scientific’ understanding since Aristotelian logic applied well to it. ”
                  —Giovanni Comandé, The Rotting Meat Error: From Galileo to Aristotle in Data Mining?

  “ Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths. ”
                  —Bertrand Russell, The Impact of Science on Society

  “ Aristotle, the most important Western philosopher of all time, was a powerful thinker. He wrote many foundational texts that shape philosophical and logical discourse to this day. He expounded on just about every topic, from math to physics to biology. He also managed to be wrong about everything. And not just mildly in error. Grievously, profoundly, perhaps even maliciously wrong to such a depth that he, more than any other single person, carries the blame for the West’s descent into the Dark Ages. Europe could not return from the depths of superstition and ignorance until it got past this man’s influence. The Enlightenment and its preceding Renaissance, in fact, represents the West finally throwing off of the iron shackles of Aristotelian thought after over a thousand years. ”
                  —Diane Stranz, Aristotle: Wrong About Everything