Imaginary Astronomies, Umberto Eco
Imaginary Astronomies
I WOULD LIKE TO MAKE it clear straightaway that in talking about imaginary geographies and astronomies I will not be dealing with astrology. The history of astrology has continually crossed paths with that of astronomy, but the imaginary astronomies and geographies I will be talking about have all now been recognized as entirely imaginary or false, whereas businessmen and heads of state still turn to astrologers for guidance. Therefore astrology is not a science, whether exact or otherwise, but a religion (or a superstition—superstitions being other people’s religions), and as such cannot be demonstrated as true or false. It is only a question of faith, and in questions of faith it is always better not to get involved, if only out of respect for those who believe.
The imaginary geographies and astronomies I will be discussing were created by people of good faith who explored the sky and the earth as they saw them—and though they were wrong, we cannot doubt their good intentions. Yet those who are still involved in astrology today know perfectly well they are describing a sky that is different from that explored and defined by astronomy, and still they continue to behave as though their conception of the sky were true. There can be no sympathy for astrologers’ bad faith. They are not people who are deceived; they are deceivers. End of argument.
As a child I dreamed over atlases. I imagined journeys and adventures in exotic lands, or I thought of myself as a Persian conqueror traveling far into the steppes of central Asia, then descending toward the seas of the Sonda to build an empire stretching from Ecbatana to the island of Sakhalin. This is perhaps why as an adult I decided to visit all those places whose names had caught my imagination, like Samarkand or Timbuktu, the Alamo or the river Amazon, and all I am missing now are Mompracem1 and Casablanca.
My astronomical exploits have been more difficult, and always practiced vicariously. A friend of mine, a Czechoslovak exile who stayed at my house in the country during the 1970s and ’80s, built telescopes and explored the sky at night from the terrace, calling me out when he found anything of interest. I came to the conclusion that only I and Rudolf II of Prague had had the privilege of lodging a Bohemian astronomer permanently under our roof, but then the Berlin Wall came down and my Bohemian astronomer returned to Bohemia.
I have found consolation in my collection of antique books—I call it the Bibliotheca semiologica curiosa, lunatica, magica, et pneumatica—and it consists entirely of books that describe falsities. It includes the works of Ptolemy but not those of Galileo, and though as a child I dreamed up my journeys over the classic modern-day atlas, I now prefer to do it over maps of Ptolemaic origin.
Is this representation of the known world of that time an imaginary one? We need to distinguish between the various meanings of the word imaginary. Some astronomies have imagined a world based on pure speculation and mystical impulses—they tell us not what the visible cosmos looks like but what the invisible and spiritual forces are that pervade it. Other astronomies, though based on observation and experience, have nonetheless conceived explanations that we regard today as wrong. Look at the explanation that Athanasius Kircher gives for sunspots, in his Mundus subterraneus of 1665, as being puffs of steam from the surface of the star. Ingenuous, but ingenious. And to remain with Kircher, this is how he applied the principles of physics and mathematical calculus, in his Turris Babel of 1679, to show that it was impossible for the Tower of Babel to rise up to heaven. Beyond a certain height, having reached the same weight as the globe itself, the tower would have caused Earth’s axis to rotate 45 degrees.
THE SHAPE OF THE EARTH
Anaximenes, in the sixth century B.C.E., spoke of a terrestrial rectangle made of earth and water, framed by the ocean, which sailed around on a sort of cushion of compressed air.
It was fairly realistic for the ancients to believe the Earth was flat. For Homer it was a disc surrounded by ocean and covered by the canopy of the heavens, and it was a flat disc for Thales and for Hecataeus of Miletus. It seemed less realistic to think it was spherical, as Pythagoras did, for mystical and mathematical reasons. The Pythagoreans had elaborated a complex planetary system in which the Earth was not even at the center of the universe. The sun was also at the edge of it, and all the planetary spheres rotated around a central fire. Each rotating sphere, moreover, produced a sound from a range of musical notes, and to establish an exact correspondence between sounds and astronomical phenomena, a nonexistent planet, the Antichthon (Counter-Earth), was also introduced. In their mathematical and musical zeal (and in their scorn of sensory experience), the Pythagoreans had not considered that if each planet produced a sound from this range of notes, their planetary music would have produced a repugnant dissonance, as if a cat had suddenly jumped onto the keys of a piano. But we still find this idea more than a thousand years later in Boethius—and let us not forget that Copernicus was also inspired by mathematical-aesthetic principles.
Subsequent demonstrations of the Earth’s roundness, though, were based on empirical observations. Ptolemy, of course, knew that Earth was round; otherwise he wouldn’t have been able to divide it into 360 degrees of longitude. But Parmenides, Eudoxus, Plato, Aristotle, Euclid, and Archimedes had already understood this. And Eratosthenes knew it in the third century B.C.E., when he had calculated fairly accurately the length of Earth’s meridian, calculating the different inclination of the sun, at midday on the summer solstice, when it reflected into the bottom of the wells of Alexandria and Syene (now Aswan). But—so far as the Earth being flat—I must digress for a moment to say that there is not only a history of imaginary astronomy, but also an imaginary history of astronomy, which still survives today in many scientific circles, not to mention in popular opinion. Try an experiment. Ask any reasonably intelligent person what Christopher Columbus wanted to demonstrate when he decided to reach the East by way of the West, and what the learned men of Salamanca persistently denied. The answer, in most cases, will be that Columbus thought the Earth was round, while the learned men of Salamanca believed it was flat and that after a short distance the three caravels would fall off the edge into the cosmic abyss.
Nineteenth-century secular thought, irritated by the fact that the church had not accepted the heliocentric theory of the universe, attributed to Christian thought (both patristic and scholastic) the idea that the Earth was flat. This idea gained force during the campaign by supporters of Darwin against all forms of fundamentalism. They wanted to show that since the church was wrong about the Earth’s being round, it could be wrong about the origin of species. They therefore took advantage of the fact that the fourth-century Christian writer Lactantius (in his Divinae institutiones) had contested the pagan theories about the roundness of the Earth by arguing that the Bible describes the universe on the model of the tabernacle. It must therefore be rectangular in form, not least because Lactantius could not accept the existence of the Antipodes, where people would have to walk around upside-down.
Then it was discovered that a sixth-century Byzantine geographer, Cosmas Indicopleustes, in his Topografia Christiana, thinking once more of the biblical tabernacle, had claimed the cosmos was rectangular, with an arch over the flat floor of the Earth.
The curved vault remained hidden from our eyes by the stereoma, in other words, by the veil of the firmament. Beneath this was the ecumene, namely, all the land on which we live, which sits on the ocean and slopes imperceptibly and continually upward to the northwest. Here there is a mountain so high that it is lost to our view and its peak disappears among the clouds. The sun, moved by angels—who also control earthquakes, and the rains and all other atmospheric phenomena—passes in the morning from the east toward the meridian, in front of the mountain, lighting up the world, and in the evening it reaches the west and disappears behind the mountain. The reverse cycle is followed by the moon and by the stars.
Cosmas also shows us the Earth as if we were looking at it from above. There is the frame of the ocean, beyond which are the lands where Noah lived before the flood. Farthest east from these lands, separated from the ocean by regions inhabited by monstrous beings, is the earthly paradise. The Euphrates, Tigris, and Ganges spring from paradise. They pass under the ocean and flow out into the Persian Gulf. The Nile takes a more tortuous route via the antediluvian lands, it enters the ocean, continues its course into the low northern regions—more accurately, into the land of Egypt—and flows out into the Golfo Romaico, the Hellespont.
As Jeffrey Burton Russell has shown in his Inventing the Flat Earth (1991), many influential books on the history of astronomy still studied at school claim that Cosmas’s theory became the prevailing view throughout the Middle Ages. They also claim the medieval church taught that the Earth was a flat disc, with Jerusalem at the center, and that the works of Ptolemy remained unknown throughout the Middle Ages. The fact is, Cosmas’s text—written in Greek, a language the medieval Christian had forgotten—became known in the
