The Complex World of Claudius Ptolemy
APRIL 01, 1959 by EDWARD P. COLESON
Dr. Coleson is Professor of Social Studies at
If there is anything the "modern" prides himself on, it is the complexity of the world of today. You hear it on every hand. Politicians are sure that the statesmen of bygone ages would have been completely baffled had they been confronted with the problems of "our modern, complex age." Many educators seem even at a loss to know what to teach or emphasize in school in "our bewildering age of rapid change, when books are obsolete even before they get the covers on." The man in the street, the average citizen, if there is such a person, may yearn to return to a hypothetical Golden Age of Simplicity which is supposedly gone forever. But, more than likely, the ordinary American has never more than cast a disdainful glance backward to what he regards as our paleolithic past. He is busy trying to peer beyond the horizon into our "Fantastic Future." This earthly paradise, just down the road, will make our present complex world seem as simple by contrast as the "horse and buggy days" appear to us now, at least so we are told.
Actually, we have nothing on the old-timers. They often got their world snarled and tangled enough to please the most fastidious devotee of the complexities of modern culture. For instance, there was old Claudius Ptolemy who flourished, as the poets say, during the first half of the second century A.D. He must have really flourished, too, as he is credited with having had more influence on geography than any other man who ever lived. Nor did his interests stop there. Certainly astronomy did not recover from the effects of his bright ideas for the next fifteen hundred years. When Galileo suffered for his Copernican heresy, it was Ptolemy, whose notions had become part of the sacred canon, who was breathing down his neck. Ideas die hard, especially if they are wrong.
Ptolemy, His Life and Times
Now we don’t really know much about Ptolemy. He made astronomical observations dated as early as the eleventh year of the Emperor Hadrian and as late as the fourteenth year of Antoninus, who picked up the additional name of Pius because he was a pretty good sort of fellow. In fact, these two Caesars were third and fourth in a series called the "five good emperors"—the only time the Romans managed to have five good ones in a row, which would be quite an accomplishment for any people. At any rate, the early and late dates for Ptolemy translate into 127 A.D. and 151 A.D., respectively, so on the basis of this, plus a few scraps of tradition, he is considered to have appeared on the scene around 90 A.D. and to have passed on to his reward about 168 A.D. That was the best time in the history of the world to be alive, too, according to Edward Gibbon, the great historian of
If a man were called to fix the period in the history of the world during which the condition of the human race was most happy and prosperous, he would without hesitation name that which elapsed from the death of Domitian (A.D. 96) to the accession of Commodus (A.D. 180).
This rascal Commodus, who was worse than Nero by a considerable margin which is no mean accomplishment, was the beginning of the end for
Historians seem to think that late in the Roman period scholars somehow tended instinctively to garner up the knowledge of the past and sort of stow it away, squirrel-like, to save it through the long Dark Ages that lay ahead. Certainly, writing "digests" summarizing the knowledge of the ancients became the fashion, whatever the motivation. That is pretty much what Ptolemy did. Any tendencies along the same line today we hope are purely coincidental.
Ptolemy’s Cosmic Problem
Now in trying to compile the astronomical knowledge of the classical period, Ptolemy needed a framework to organize his cosmos around. There were obviously two possible centers for his systern, the earth and the sun; and he was well aware of the alternatives, as, indeed, Greeks had been long before his time. In fact, one of his predecessors at the Library of Alexandria, Eratosthenes by name, had even measured the circumference of the earth some three centuries before and with surprisingly accurate results, too. Perhaps he got about 25,000 miles which is the approximation we use today, or maybe a couple or three thousand more, we aren’t sure, but even that would be an accomplishment. You try it! Ptolemy, as part of his self-appointed task of reordering the world, trimmed Eratosthenes’ figure down to a mere 18,000 miles, which, some thirteen hundred years later, led a Genoese navigator named Columbus to get the absurd notion that the Eurasian land mass extended pretty well around the globe so that he could easily reach the East by sailing west. But so much for that. This was only one of his minor errors.
When confronted with the problem of choosing a center for his solar system, Ptolemy missed his way altogether. Now primitive peoples have always assumed that the earth was flat with a huge inverted bowl turned over it, with the stars mounted like jewels in this vault of heaven. Now the fixed stars, as we call them, always stay in nice neat patterns—Orion, the Gemini, the Pleiades, and the rest—and go trooping along in perfect formation through the night toward the western horizon, except those around the Pole Star which seem slowly to circle that star. The sun, of course, was a special case: some giant in the east made a long pass during the day and another fellow in the west intercepted it and made an end run during the night all ready to start over the next morning, or at least that is the modern version of the story. But our friend Ptolemy was not a superstitious, slant-browed cave man; he was the end-product of centuries of learning and culture, and had the vast Alexandrian Library at his disposal.
Still the problem was not a simple one even for him. He realized, and correctly, that the near stars should appear to shift with respect to the far ones, parallax as it is called, if the earth went around the sun. But no parallax was evident with the naked eye. Nor could he get over another problem which was closer by. He knew that if he had his earth go around the sun to make his year, it would have to rotate on its axis every day to produce night and day. But if the earth went around in 24 hours, that meant a point on the equator would be moving at a velocity of over a thousand miles an hour (about 750 on his smaller globe) . If the earth were rotating at this furious speed, Ptolemy reasoned, there should be a terrific gale, much as if you stuck your head out the window of a jet plane. No such wind was apparent, so the earth stood still and everything else went around it. Ptolemy sensed that there was something whacky about the whole arrangement, but it was the best he could do with the evidence at hand.
Now a stationary earth works as well as any other kind—almost. Of course, there were some engineering problems involved, such as how the host of heaven got around the earth every day which would involve speeds infinitely greater than the mere 750 that had bothered him. But at least they were remote, and he had taken care of the problems at hand which is what all good politicians have learned to do since. There was only one really serious difficulty: the problem of the planets.
The Maladjusted Planets
Since men began to observe the stars in the remote past, it was noticed that the host of heaven marched past in the night in perfect order, each star maintaining its place within its pattern (constellation) faithfully from year to year (although the heavens aren’t changeless over the ages). How‑
ever, there were a few bright and conspicuous stars that were a law unto themselves; they appeared to wander among their fellows. You would find one as an intruder in a given constellation now, and a few months later it would have moved on into another. Hence, their name planeta, which means wanderer.
Now fitting these maladjusted members of the celestial family into his cosmic scheme was no easy assignment, since they not only slowly strayed where they would, but even executed weird loops in their paths among the stars on occasion. But Ptolemy was equal to the task. The Greeks had decreed that all orbits should be circles, since a circle was the symbol of perfection, so Ptolemy was stuck with that figure.
However, there was no limit to the number of circles he could use; they weren’t rationed. He, therefore, put his planet—Mars, for example—on the periphery of a second circle whose center, an imaginary point in space, followed a circular path about the earth as in Figure 2. The scheme, although a little complicated, worked quite well as should be evident from Figure 1. The apparent path of a planet as the consequence of this double motion was looped at intervals which is exactly what happens—or at least appears to happen—periodically in the heavens. So far so good.
Complexity Ad Absurdum
However, there was still one little catch to the whole arrangement. If an astronomer tried to project the system into the future and predict the position of a planet for some night years ahead, he was always in error. But that could be remedied. Why not a double epicycle as in Figure 3? The planet in question was now mounted on the circumference of an imaginary second orbit, whose center followed a circular path whose center in turn went about the earth. Now that ought to do it. It should have, but the more involved system didn’t quite work either. But still astronomers didn’t give up hope, perhaps other epicycles revolving on the previous ones would secure a better fit.
In the ensuing centuries that elapsed before Copernicus and Kepler straightened out the celestial tangle in the sixteenth and early seventeenth centuries, industrious scholars complicated the theoretical structure beyond belief. Still, the computed paths, the theory, did not fit the facts of observation for very long into the future. The planets soon got out of order no matter how involved the system became. Arabian astronomers carried on while the Western World was sunk in the night of the Dark Ages. Finally, each planet was fitted out with 40 to 60 epicycles, each turning on the other, a literal nightmare of celestial clockwork. Still the system did not work very well for very long. An old story has it that King Alphonso X of
Strangely enough, the revolution of Copernicus consisted simply of choosing a new center, the sun instead of the earth. The resulting system as worked out more fully by Kepler was childlike in its simplicity. Put the sun in the center and let the planets just go around it, that’s all. The loops are an optical illusion noted when the earth passes the outer planets on the way around, just as a moving train appears to stop and back up when you pass it. The Ptolemaic theory had fallen under the ponderous load of its own complexity. The incredible thing is that men who were intellectually capable of devising such a fabulously involved theoretical structure were not wise enough to see that it was unnecessary.
The Moral of the Story
It is regrettable that astronomy is practically the forgotten science. If only our contemporaries were acquainted with Claudius Ptolemy, then when one of our complicated schemes failed to work—another farm program, some monetary hocus – pocus, or other economic witchcraft whereby we may all live like kings without doing much of anything—one might suggest: "What we need is another epicycle. That would straighten out everything." For somehow one cannot view our "complex, modern world" without being overwhelmed as King Alphonso X was with the feeling that the world just isn’t naturally like that nor does it need to be.
Let those who believe that the present chaos is the inevitable fruitage of the Industrial Revolution examine the record. Back in the days of the Founding Fathers of this Republic when craftsmen still plied their trades, Europeans did quite well complicating what we have regarded as their simple world and exported more of the same to their colonies, as should be evident from the following:
In every quarter, and at every moment, the hand of government was felt. Duties on importation, and duties on exportation; bounties to raise up a losing trade, and taxes to pull down a remunerative one ; this branch of industry forbidden, and that branch of industry encouraged; one article of commerce must not be grown, because it was grown in the colonies, another article might be grown and bought, but not sold again, while a third article might be bought and sold, but not leave the country. Then, too, we find laws to regulate wages; laws to regulate prices; laws to regulate profits ; laws to regulate the interest of money; custom-house arrangements of the most vexatious kind…. and the inconvenience suffered. . . . in order that industry might thrive. . . .
The first inevitable consequence was that, in every part of
-Henry Thomas Buckle
The Obvious and Simple System
Remember Ptolemy’s scheme was incredibly complicated, learned—and wrong. Copernicus found a new center, and order just naturally grew out of chaos. One is reminded of the words of Adam Smith: "All systems either of preference or of restraint, therefore, being thus completely taken away, the obvious and simple system of natural liberty establishes itself of its own accord…." The obvious and simple system of natural liberty . .. liberty establishes itself … yes, liberty!