Edge: Thaler's Question

[bystander]

http://edge.org/3rd_culture/thaler10/th ... index.html - 59 respondents.

The flat earth and geocentric world are examples of wrong scientific beliefs that were held for long periods.
Can you name your favorite example and for extra credit why it was believed to be true?

[Ann]

As a Swede and a Scandinavian, I am proud of the achievements of Danish Tycho Brahe in the 16th century. Brahe was wrong about the layout of the cosmos, however, and he ended up believing in a mostly Ptolemaic, Earth-centered universe, where the Sun and the stars orbited the Earth, but where the other planets in our solar system orbited the Sun.

Here is a great summary of the achievements of Tycho Brahe and a fine explanation for why he believed in the sort of cosmos that he did, for partly scientific reasons:

http://cseligman.com/text/history/braheastro.htm

The long and short of why Tycho Brahe believed in his strange, mostly Earth-centered but partly Sun-centered universe is that he couldn't detect any parallaxes in the stars. Brahe was an astoundingly excellent observer for his time and he had great faith in his own observations. If he couldn't detect any parallaxes in the stars, then either the stars must be orbiting the Earth in an Earth-centered universe or else they must be truly unimaginably far away, and Brahe couldn't - or wouldn't - believe that the stars were so far away.

At the same time he realized that the other planets must be orbiting the Sun, because otherwise they wouldn't show any retrograde motion in the sky.

Ann

[Chris Peterson]

The flat earth and geocentric world are examples of wrong scientific beliefs that were held for long periods.
Can you name your favorite example and for extra credit why it was believed to be true?

It's a myth that there was ever much belief in a flat earth among educated people- at least, not for the last few thousand years. And I'd argue that neither of these beliefs could be called "scientific" in anything close to the modern sense. Indeed, it was the development of modern scientific methods that very rapidly demolished the earlier, philosophical viewpoint that the Earth was at the center of the Universe, or the center of the Solar System.

[neufer]

It's a myth that there was ever much belief in a flat earth among educated people- at least, not for the last few thousand years.

Except, that the land-based educated Chinese were somewhat Confuciused.

In the 2nd century BC, Crates of Mallus devised a terrestrial sphere which divided the Earth into four continents, separated by great rivers or oceans, with people presumed to be living in each of the four regions. Opposite the oikumene, the inhabited world, were the antipodes, considered unreachable both because of an intervening torrid zone (equator) and the ocean. This took a strong hold on the medieval mind.

---

<<Most pre-modern cultures have had conceptions of a flat Earth, including ancient Greece until the classical period, the Bronze Age and Iron Age civilizations of the Ancient Near East until the Hellenistic period, Ancient India until the Gupta period (early centuries AD) and China until the 17th century.

The paradigm of a spherical Earth was developed in ancient Greek astronomy, beginning with Pythagoras (6th century BC), although most Pre-Socratics retained the flat Earth model. Aristotle accepted the spherical shape of the Earth on empirical grounds around 330 BC, and knowledge of the spherical Earth gradually began to spread beyond the Hellenistic world from then on. The Earth's circumference was first determined around 240 BC by Eratosthenes. Eratosthenes knew that in Syene, in Egypt, the Sun was directly overhead at the summer solstice, while he estimated that the angle formed by a shadow cast by the Sun at Alexandria was 1/50th of a circle. He estimated the distance from Syene to Alexandria as 5,000 stades, and estimated the Earth's circumference was 250,000 stades. Subsequently, ignorance of the size of a stadia caused problems both to the Arabs and to Christopher Columbus.

In ancient China, the prevailing belief was that the Earth was flat and square, while the heavens were round: "Chinese thought on the form of the Earth remained almost unchanged from early times until the first contacts with modern science through the medium of Jesuit missionaries in the 17th century. While the heavens were variously described as being like an umbrella covering the Earth (the Kai Tian theory), or like a sphere surrounding it (the Hun Tian theory), or as being without substance while the heavenly bodies float freely (the Hsüan yeh theory), the Earth was at all times flat, although perhaps bulging up slightly." In a passage of Zhang Heng's cosmogony: "Heaven takes its body from the Yang, so it is round and in motion. earth takes its body from the Yin, so it is flat and quiescent". It has been suggested that seafarers probably provided the first observational evidence that the Earth was not flat. Greek thalassocracy was receptive to the idea, unlike the Chinese, whose cosmology was firmly land-based. In the 2nd Century BC Chinese astronomers effectively inverted Eratosthenes' calculation of the curvature of the earth in order to calculate the height of the sun above the earth. By assuming the earth to be flat, they arrived at a distance of 100,000 li.

In early Egyptian and Mesopotamian thought the world was portrayed as a flat disk floating in the ocean. A similar model is found in the Homeric account of the 8th century BCE in which "Okeanos, the personified body of water surrounding the circular surface of the Earth, is the begetter of all life and possibly all the gods,". The Hebrew Bible described a circular earth with a solid roof, surrounded by water above and below. A cosmological view prevailed in India that held the Earth is a disc that consists of four continents grouped around the central mountain Meru like the petals of a flower. An outer ocean surrounds these continents. This view was elaborated in traditional Jain cosmology and Buddhist cosmology, which depicts the world (in this case solar system/universe and not Earth) as a vast, flat oceanic disk (of the magnitude of a small planetary system), bounded by mountains, in which the continents are set as small islands.

Lucretius (1st. c. BC) opposed the concept of a spherical Earth, because he considered that in an infinite universe there was no center towards which heavy bodies would tend, thus he considered the idea of animals walking around topsy-turvy under the Earth to be absurd. But by the 1st century AD, Pliny the Elder was in a position to claim that everyone agrees on the spherical shape of Earth, although there continued to be disputes regarding the nature of the antipodes, and how it is possible to keep the ocean in a curved shape. Pliny also considers the possibility of an imperfect sphere, "shaped like a pinecone". Ptolemy derived his maps from a curved globe and developed the system of latitude, longitude, and climes. His Almagest was written in Greek and only translated into Latin in the 11th century from Arabic translations. But once it was known, it remained the basis of European astronomy throughout the Middle Ages. In late antiquity such widely read encyclopedists as Macrobius (4th c.) discussed the circumference of the sphere of the Earth, its central position in the universe, the difference of the seasons in northern and southern hemispheres, and many other geographical details. In his commentary on Cicero's Dream of Scipio, Macrobius described the Earth as a globe of insignificant size in comparison to the remainder of the cosmos.

The Jerusalem Talmud says that Alexander of Macedon (Alexander the Great) was lifted by birds to the point that he saw the curvature of the Earth. From Late Antiquity, and from the beginnings of Christian theology, knowledge of the sphericity of the Earth had become widespread. There was considerable misunderstanding illustrated by the debate concerning the possibility of the inhabitants of the antipodes: Saint Augustine (354–430) argued against assuming people inhabited the antipodes: "But as to the fable that there are Antipodes, that is to say, men on the opposite side of the earth, where the sun rises when it sets to us, men who walk with their feet opposite ours that is on no ground credible. And, indeed, it is not affirmed that this has been learned by historical knowledge, but by scientific conjecture, on the ground that the earth is suspended within the concavity of the sky, and that it has as much room on the one side of it as on the other: hence they say that the part that is beneath must also be inhabited. But they do not remark that, although it be supposed or scientifically demonstrated that the world is of a round and spherical form, yet it does not follow that the other side of the earth is bare of water; nor even, though it be bare, does it immediately follow that it is peopled. It is too absurd to say, that some men might have taken ship and traversed the whole wide ocean, and crossed from this side of the world to the other, and that thus even the inhabitants of that distant region are descended from that one first man."

* The monk Bede (c.672 – 735) wrote in his influential treatise on computus, The Reckoning of Time, that the Earth was round ('not merely circular like a shield [or] spread out like a wheel, but resembl[ing] more a ball'), explaining the unequal length of daylight from "the roundness of the Earth, for not without reason is it called 'the orb of the world' on the pages of Holy Scripture and of ordinary literature. It is, in fact, set like a sphere in the middle of the whole universe." (De temporum ratione, 32). The large number of surviving manuscripts of The Reckoning of Time, copied to meet the Carolingian requirement that all priests should study the computus, indicates that many, if not most, priests were exposed to the idea of the sphericity of the Earth.

Thomas Aquinas, in his Summa Theologica, wrote, "The physicist proves the earth to be round by one means, the astronomer by another: for the latter proves this by means of mathematics, e.g. by the shapes of eclipses, or something of the sort; while the former proves it by means of physics, e.g. by the movement of heavy bodies towards the center, and so forth."

There has never been in Islam a significant belief in a flat earth. In the 9th century Abbasid Caliphate, most of the Greek works of cosmology from Constantinople, including Aristotle's De caelo and Ptolemy's Almagest were translated into Arabic in the House of Wisdom in Baghdad. Muslim scholars who held to the round Earth theory used it in an impeccably Islamic manner, to calculate the distance and direction from any given point on the Earth to Makkah (Mecca). This determined the Qibla, or Muslim direction of prayer.>>

[bystander]

It's a myth that there was ever much belief in a flat earth among educated people- at least, not for the last few thousand years. And I'd argue that neither of these beliefs could be called "scientific" in anything close to the modern sense. Indeed, it was the development of modern scientific methods that very rapidly demolished the earlier, philosophical viewpoint that the Earth was at the center of the Universe, or the center of the Solar System.

This is addressed in some of the responses:

GEOFFREY CARR
Science Editor, The Economist

Believing that people believed the Earth was flat is a good example of a modern myth about ancient scientific belief. Educated people have known it was spherical (and also how big it was) since the time of Eratosthenes. That is pretty close to the beginning of any system of thought that could reasonably merit being called scientific...

CHARLES SIMONYI
Computer Scientist, International Software; Former Chief Architect, and Distinguished Engineer, Microsoft Corporation
...
I am of course aware of the currently popular belief that "flat earth" was somehow a widely held "scientific" idea, but I do not know what evidence supports this belief. It was certainly not part of the Antique inheritance (who had pretty good estimates for the diameter of the earth and excellent estimates for the ratio of Earth's and Moon's diameters); It was not part of Aristotle, or Aquinus, or any of the authorities that the Church relied on. No doubt, there were some creation myths or fanciful publications that might have illustrated the world as being flat but it is a stretch to call these "scientific" even by standards of the age, when learned men would have been able to refute such a thesis easily — and probably did as part of their exams.

With the geocentric world it is a different matter — geocentrism was indeed scientifically held (with Ptolemy being the best proponent) and it is indeed false

[neufer]

The current United Nations emblem was approved on 7 December 1946.

---

Voliva's flat earth map. Modern Mechanics & Invention, 1931.

---

[owlice]

Flate Art? You have your own website now!

[neufer]

Flate Art? You have your own website now!

Well, I AM pro-conflate.