The Ptolemaic System


The System Equant
Terrestrial Ball The Talmud
Money in the Bank Poets
Dark Ages Dignity


The System

The description of the universe systematized by Claudio Ptolemy is science, not mythology; it has high predictive value. If you want to know when there will be an eclipse of the sun or moon, or where Venus will be in the night sky six years from this date, Ptolemy's system works as well as Copernicus'. The heavens are proposed to move spherically because, among other things:



  • “In a word, whatever figure other than the spherical be assumed for the movement of the heavens, there must be unequal linear distances from the earth to parts of the heavens, wherever or however the earth be situated, so that the magnitudes and angular distances of the stars with respect to each other would appear unequal to the same people within each revolution, now larger now smaller. But this is not observed to happen.”
  • (Ptolemy, Almagest, Book 1, 3. That the Heavens Move Spherically).


Andreas Cellarius, Map of the Ptolemaic System


The earth in this system is round, though some people insist otherwise. Ptolemy thought the earth was spherical because, among other reasons:


  • “Now, that also the earth taken as a whole is sensibly spherical, we could most likely think out in this way. For again it is possible to see that the sun and moon and the other stars do not rise and set at the same time for every observer on the earth, but always earlier for those living towards the orient and later for those living towards the occident. For we find that the phenomena of eclipses taking place at the same time, especially those of the moon, are not recorded at the same hours for everyone -- that is, relatively to equal intervals of time from noon; but we always find later hours recorded for observers towards the orient than for those towards the occident. And since the differences in the hours is found to be proportional to the distances between the places, one would reasonably suppose the surface of the earth spherical, with the result that the general uniformity of curvature would assure every part's covering those following it proportionately. But this would not happen if the figure were any other. . .”
  • (Ptolemy, Almagest, Book 1, 4. That the Earth, Taken as a Whole, is Sensibly Spherical).


This seventeenth century artist has taken the liberty of enlarging the earth for clarity. In Ptolemy's system, the earth is a point by comparison with the sphere of the fixed stars:


  • “Now, that the earth has sensibly the ratio of a point to its distance from the sphere of the so-called fixed stars gets great support from the fact that in all parts of the earth the sizes and angular distances of the stars at the same times appear everywhere equal and alike, for the observations of the same stars in the different latitudes are not found to differ in the least.

  • “Moreover, this must be added: that sundials placed in any part of the earth and the centers of armillary spheres can play the role of the earth's true center for the sightings and the rotations of the shadows, as much in conformity with the hypotheses of the appearances as if they were at the true midpoint of the earth.”
  • (Ptolemy, Almagest, Book 1, 6. That the Earth Has the Ratio of a Point to the Heavens).


The system is geocentric. While we envision earth hurtling through space, while turning about on its axis, in Ptolemy's system, everything else moves, not the earth. Ptolemy had heard speculation to the contrary:



  • “Now some people, although they have nothing to oppose to these arguments, agree on something, as they think, more plausible. And it seems to them there is nothing against their supposing, for instance, the heavens immobile and the earth as turning on the same axis from west to east very nearly one revolution a day. . .for us to grant these things, they would have to admit that the earth's turning is the swiftest of absolutely all the movements about it because of its making so great a revolution in a short time, so that all those things that were not at rest on the earth would seem to have a movement contrary to it, and never would a cloud be seen to move toward the east nor anything else that flew or was thrown into the air. For the earth would always outstrip them in its eastward motion, so that all other bodies would seem to be left behind and to move towards the west.”
  • (Ptolemy, Almagest, Book 1, 7. That the Earth Does Not in any Way Move Locally).


The architects of Ptolemy's astronomy could not fathom why a moving earth would not leave behind it a garbage stream like the wake of a negligent cruise liner, a trail of dropped items like the clues left by a fleeing criminal. Why would your dropped keys, not tethered to your hand nor to the ground, not fall somewhere other than directly below where you dropped them, as they are always observed to do, if the earth beneath your feet has moved in the mean time? It took the genius of Galileo Galilei to explain this, thus making the world safe for heliocentrism.

Aristotle
 On the Heavens 


Equant

Above it was mentioned that Ptolemy's system is geocentric. That's true. . .approximately. Ptolemy used several different constructions to model the orbits, including eccentric circles and the equant. The heavenly bodies are not necessarily orbiting around the center of the earth, but around a (moving) point somewhere in the vicinity. Moreover these big circles are carrying epicycles, smaller circles along for the ride, stubbornly pursuing their own motion even as they are carried along the larger orbit. The system is dauntingly complex. Copernicus, though retaining epicycles, was able to simplify the system by running the planets around the sun.

Proponents of the Ptolemaic system understood that the system had departed from perfect geocentricity: "...for according to Ptolemy, the motion of the planets is in eccentrics and epicycles, which are motions, not around the middle of the world, which is the earth's center, but around certain other centers." (Thomas Aquinas, 'On the Heavens,' Book I, Lecture 3, 28). The system ultimately departs from its starting premises of geocentricity and uniform circular motion, and ends up vibrating and shimmying like a washing machine with an unbalanced load.

Terrestrial Ball

Ptolemy's system was originated not by himself but by earlier astronomers. Its contemporary acceptance was not universal, but the widespread belief that has somehow established itself that everyone prior to Christopher Columbus thought the earth was flat is baseless. When the hymn-writer sings,

"Let every kindred, every tribe,
On this terrestrial ball,
To Him all majesty ascribe,
And crown Him Lord of all;
To Him all majesty ascribe,
And crown Him Lord of all!
           (All Hail the Power of Jesus' Name)

...it is foolish to insist the question of flat-earthism remains open. And writers in antiquity also called the earth a globe or an orb:

"Military discipline jealously conserved won the leadership of Italy for Roman empire, bestowed rule over many cities, great kings, mighty nations...made it from its origin in Romulus' little cottage into the summit of the entire globe [terrarum orbis]." (Valerius Maximus, 'Memorable Doings and Sayings,' Book II.8).
"For he wisely realized that increase for Roman empire was to be asked for in the days when triumphs were sought on the near side of the seventh milestone, but for a people that possessed the greater part of the whole globe [terrarum orbis] it would be greedy to ask for more and abundantly fortunate if they lost nothing of what was already theirs." (Valerius Maximus, 'Memorable Doings and Sayings,' Book IV.1).
"The magnanimous monarch, who had already embraced the entire globe [terrarum orbem] by his victories or expectations, in so few words shared himself with him companion." (Valerius Maximus, 'Memorable Doings and Sayings,' Book IV.7).
"The signal clemency of the divine leader kept this father safe, but who would not think his daring more than human in that he did not yield to one to whom the whole world [terrarum orbis] succumbed?" (Valerius Maximus, 'Memorable Doings and Sayings,' Book V.7).

Since this language is boiler-plate, it comes as no surprise when Eusebius puts the phrase in the mouth of the Emperor Constantine:

"The stars move in no uncertain orbits round this terrestrial globe." (Eusebius, The Life of Constantine, Book 2, Chapter 58).

This language did not thereafter pass out of fashion:

"For all those things, which at present you witness in the Church of God, and which you see to be taking place under the name of Christ throughout the whole world [totum orbem terrarum], were predicted long ages ago. . .It was foretold not only by the prophets, but also by the Lord Jesus Christ Himself, that His Church would exist throughout the whole world [universum orbem terrarum], extended by the martyrdoms and sufferings of the saints. . ." (Augustine, On Catechizing the Uninstructed, Chapter XXVII, Section 53.)

It is eccentric to say the very least for speakers who believe the earth is flat to call it an 'orb' or 'globe.'




Talmud

Did the Jews agree with the pagans on the rotundity of the earth? One answer is found in the Talmud, which discusses statuary. Is it an ornamentation to a city, or idolatry? According to the Rabbis, if a statue, of an emperor, say, holds a ball in his hand, this suggests he rules the whole world, the prerogative of God:

"...Rabbah said: There is difference of opinion [with regard to statues] in cities;  but as for those in villages all agree that they are prohibited.

"BUT THE SAGES DECLARE, [AN IMAGE] IS NOT PROHIBITED etc. [It is prohibited when holding] a staff, because [the implication is] that it rules the whole world as with a staff. [...] [It is prohibited when holding] an orb, because [the implication is] that it grasps the whole world as though it were a ball."
(Babylonian Talmud, Abodah Zara 41a).

But why would holding a ball convey this message, if it were thought the earth is flat?

Money in the Bank

A round object turns up on Roman coins, such as this one depicting the Emperor Caracalla holding the world in his hand:

Emperor Caracalla

You would think the atheists would be more familiar with the orb, because it turns up in their own cultural monuments. Director Sergei Eisenstein's epic silent movie 'October,' commemorating the Bolshevik Revolution, begins with the heroic proletariat tearing down a monumental statue of Czar Alexander III. The word 'Czar,' like the German 'Kaiser,' is a naturalization of 'Caesar,' and the Russian Czar inherited some of Caesar's attributes as well as his name, including the orb. So what is Alexander holding in Eisenstein's classic film? An orb, of course. Here is a screen grab from the movie:

Czar Alexander III statue falling from Sergei Eisenstein's 'October'


Someone was not thinking clearly in selecting the orb as a token of flat world domination.

Poets

Some people are willing to concede that the astronomers of antiquity realized the earth was round, as indeed cannot be denied. They allege, however, that most people did not know this. While there are dissenters throughout the period, in fact most people had good reason to know this. A rotund earth turns up in popular poetry, like Virgil's Georgics:

"As our globe rises steep to Scythia and the Riphaean crags, so it slopes downward to Libya's southland. One pole is ever high above us, while the other, beneath our feet, is seen of black Styx and the shades infernal. . .There, men say, is either the silence of lifeless night, and gloom ever thickening beneath night's pall; or else Dawn returns from us and brings them back the day, and when on us the rising Sun first breathes with panting steeds, there glowing Vesper is kindling his evening rays." (Virgil, Georgics, Georgic 1).

Dark Ages

The knowledge of a rotund earth was never lost; Thomas Aquinas, writing in the middle ages, boasts of the improved number his contemporaries had worked up for the circumference of the earth:

"But according to the more careful measurement of present-day astronomers, the earth's circumference is much less, i.e., 20,000 times 1,000 paces and 400, as Al Fargani says; or 180,000 stades, as Simplicius says — which is about the same, since 20,000 is 1/8 of 160,000. . .And so, from all of this, we can argue that the earth's quantity is not only spherical, but not large in comparison to the sizes of the other stars." (Thomas Aquinas, Commentary on Aristotle's De Caelo, 'On the Heaven,' Book II, Lecture 28, 543).

Though these new and improved numbers are too small, they are encouraging: "And therefore, we would not consider as very absurd the view of those who wish to link, on the basis of similarity and nearness, the region situated in the far west about the pillars of Hercules (which Hercules set up as a memorial of his victory), and the region in the far east about the Indian Ocean, and who say there is one sea, the Ocean, bordering on both places. And they make a conjecture as to the similarity of both places from the elephants which arise in both places but are not found in the regions between them." (Thomas Aquinas, 'On the Heavens,' Book II, Lecture 28, 542).

People who want to criticize the church's loyalty to Ptolemaic astronomy will have no difficult finding fault with Ptolemy's model. The system is geocentric, but not with respect to a fixed point; the whole contraption does a little shimmy, like a grocery cart with a bumpy wheel. Why they feel to need to make up a non-existent feature: a flat earth,— is a mystery.

The Center The Magnificat
Pagan Philosophy Galileo's Crime
The Stable Earth The Moving Sun
Tycho Brahe Pagan Religion



What is the music of the spheres?:

Cicero
 Scipio's Dream 


Dignity

Atheists commonly assume that the earth occupies the central position in Ptolemy's astronomy because the earth is taken to be the most important. This ancient astronomy, in other words, is assumed to operate on a principle of wish fulfillment, though the people who so assume do not normally admit their own 'science' proceeds from a principle of wish fulfillment. In fact the earth is considered, by those who laid out the parameters of this astronomy, not to be the best and noblest, but the lowest (literally), of the constituents of the universe.


  • “And according to Aristotle's principles, their order in dignity corresponds to the order of their position, on the ground that the higher sphere contains the lower and the container is more noble and more formal than the contained, as is said in Physics IV and as will be said later in the section treating of the earth.
  • “According to this, then, it must be understood that the optimum in things is permanence, which, in separated substances, is realized without any motion at all, and whatever of permanence exists in lower things is derived thence. And this explains why the outermost heaven, which is nearest to the separated substances, is by its diurnal motion the cause of the sempiternity and permanence of things; on which account, it ranks highest in resembling the first principle.”
  • (Thomas Aquinas, Commentary on Aristotle's 'On the Heavens,' Book II, Lecture 18, Section 468).

There is a hierarchy of importance assigned to the constituents of this astronomy, but that hierarchy runs in reverse order from what the atheists assume: the earth, occupying the 'sublunary sphere,' is the realm and change and decay, by contrast with the more excellent and enduring heavens. The earth does not occupy a privileged position, but a lowly one, in every sense of the word. Thomas Aquinas, who adopts this system, ventures to call it "ignoble:" "And therefore, in the whole universe, just as the earth which is contained by all, being in the middle, is the most material and ignoble among bodies, so the outermost sphere is most formal and most noble, while among the elements fire is above all containing and formal." (Thomas Aquinas, Commentary on Aristotle's 'On the Heavens,' Book II, Lecture 20, Section 485).

The ancient pagans deified the heavenly bodies, and in Aristotle's case, this tendency is especially conspicuous with regard to the outermost sphere. This whole conception is so shot through with pagan thought-forms and expectations it is a wonder Christians like Thomas felt comfortable with it. It is striking that the Medievals were so lacking in self-confidence they were unwilling to strike out on their own; the ancient Greek astronomy was already more than 1,500 years old when Thomas took it up, with only minor tweaks and modifications. The development of this astronomical system by pagan Greeks in the centuries before Christ was not, contra the atheists, an instance of Christian wish-fulfillment.

The atheists are a creative people, and just as they are determined to assign features to the Ptolemaic system which it does not have, such as a flat earth, they are also determined to 'find' an unmet Christian theological need which the pagan Ptolemy anticipated and to which he fit a solution as tightly as a hand to a glove. But the God of the Bible is omnipresent: "Whither shall I go from thy spirit? or whither shall I flee from thy presence?" (Psalm 139:7), He is a spirit: "God is a Spirit: and they that worship him must worship him in spirit and in truth." (John 4:24); He does not stand in need of situating. Thomas did not adopt this celestial architecture because it was uniquely well-suited to the Christian world-view, but because it was the most successful scientific astronomy known to him.