Ptolemy
The virtually canonical example is the Ptolemaic system. Today we know that for centuries humankind acted on its belief in a false representation of the cosmos. People sought out every possible argument that could compensate for the falsity of the image; they invented epicycles and deferents; finally, with Tycho Brahe, they tried to move all the planets around the sun, while allowing the sun to continue moving around the earth.
On the basis of the Ptolemaic image not only did Dante Alighieri act (small harm done), but, worse, so did the Phoenician navigators, Saint Brendan, Eric the Red, and Christopher Columbus (and one of them was somehow the first to arrive in America). And further, on the basis of this false hypothesis, people managed to divide the globe into parallels and meridian degrees, as we still do, having simply shifted the prime meridian from the Canaries to Greenwich.
The example of Ptolemy, which, by association, immediately calls up the unfortunate story of Galileo, would seem to suggest that, with secular arrogance, I confine my history of the power of falsehood to instances where dogmatic thought rejected the light of truth. But here is a story from the opposite position, the story of another falsity, slowly constructed by modern secular thought to defame religious thought.
The Flat Earth
Try this experiment. Ask an ordinary person what Christopher Columbus wanted to prove when he set out to reach the Orient by way of the Occident and what it was that the learned men of Salamanca stubbornly denied, trying to prevent his voyage. The reply, in most cases, will be that Columbus believed the earth was round, whereas the Salamanca sages believed it was flat and hence thought that, after sailing a short distance, the three caravels would plunge into the cosmic abyss.
Nineteenth-century secular thought, irritated by the Church’s refusal to accept the heliocentric hypothesis, attributed to all Christian thought (patristic and scholastic) the idea that the earth was flat. The nineteenth-century positivist and anticlerical made a meal of this cliché, which, as Jeffrey Burton Russell has demonstrated,1 was strengthened during the battle the supporters of Darwinian theory joined against every form of fundamentalism. It was a matter of demonstrating that, as the churches had erred about the sphericity of the earth, so they could err also about the origin of species.
The Darwinians then exploited the fact that a Christian author of the fourth century, such as Lactantius in his Institutiones divinae, having to accept many biblical passages in which the universe is described as modeled on the tabernacle, hence quadrangular in form, opposed the pagan theories of the earth’s roundness, also because he could not accept the idea that there existed antipodes where men would have to walk with their heads down and their feet in the air.
Finally it was discovered that a Byzantine geographer of the fourth century, Cosmas Indicopleustes, had argued that the cosmos was rectangular, with an arc that dominated the flat pavement of the earth (once again the archetype was the tabernacle). In his authoritative book History of Planetary Systems from Thales to Kepler, J. L. E. Dreyer admits that Cosmas was not an official representative of the Church, while giving ample space to his theory. E. J. Dijksterhuis, in his Mechanization of the World Picture (originally in Dutch), asserts that the theory of Cosmas remained the prevalent opinion for many centuries, even though he also concedes that Lactantius and Cosmas must not be considered representatives of the scientific culture of the Church Fathers.2
The fact is that Christian culture, in the early years and in the Middle Ages, left Lactantius to stew in his own juice, and the text of Cosmas, written in Greek and therefore in a language the Christian Middle Ages had forgotten, was revealed to the Western world only in 1706, in Montfaucon’s Nova collectio patrum et scriptorum graecorum. No medieval author knew Cosmas, and his text was considered an authority of the “Dark Ages” only after its English publication in 1897!
Naturally Ptolemy knew the earth was round, otherwise he would not have been able to divide it into three hundred and sixty degrees of meridian. Eratosthenes also knew it, for in the third century before Christ he calculated with reasonable accuracy the diameter of the earth. Pythagoras knew it, too, as did Parmenides, Eudoxius, Plato, Aristotle, Euclid, Aristarchus, and Archimedes. And it turns out that the only ones who did not believe it were two materialists, Leucippus and Democritus.
Macrobius and Martianus Capella were also well aware that the earth was round. As for the Church Fathers, they had to deal with the biblical text, which spoke of that tiresome tabernacle form, but Augustine, even if he did not have firm notions on the subject, knew those of the ancients and conceded that the sacred text was speaking metaphorically. His position is somewhat different, though fairly common in patristic thought: as knowledge of the earth’s form will not save the soul, the question seemed to him of scant interest. Isidore of Seville (who was surely not a model of scientific precision) calculates at a certain point that the equator was eighty thousand stadii in length. Could he have thought the earth was flat?
Even a high school student can easily deduce that, if Dante enters the funnel of the Inferno and emerges on the other side to see unknown stars at the foot of the mount of Purgatory, then he must have known very well that the earth was round. But forget Dante, to whom we have a tendency to attribute every virtue. The fact is that Origen and Ambrose were of the same opinion, and in the scholastic age a spherical earth was conceived and spoken of by Albertus Magnus and Thomas Aquinas, Roger Bacon, John of Holywood, Pierre d’Ailly, Egidius Romanus, Nicolas Oresme, and Jean Buridan, to name only a few.
So what was the big argument all about in the time of Columbus? The sages of Salamanca had, in fact, made calculations more precise than his, and they held that the earth, while assuredly round, was far more vast than the Genoese navigator believed, and therefore it was mad for him to attempt to circumnavigate it in order to reach the Orient by way of the Occident.
Columbus, on the contrary, burning with a sacred fire, good navigator but bad astronomer, thought the earth smaller than it was. Naturally neither he nor the learned men of Salamanca suspected that between Europe and Asia there lay another continent. And so you see how complicated life is, and how fragile are the boundaries between truth and error, right and wrong. Though they were right, the sages of Salamanca were wrong; and Columbus, while he was wrong, pursued faithfully his error and proved to be right—thanks to serendipity.
But read what Andrew Dickson White says in his History of the Warfare of Science with Theology in Christendom.3 True, in these two thick volumes his aim is to list every instance in which religious thought impeded the advancement of science, but as he is an informed and honest man he cannot conceal the fact that Augustine, Albertus Magnus, and Aquinas knew very well that the earth was round. He adds, however, that to sustain this idea, they had to combat dominant theological thought. But dominant theological thought was represented, in fact, by Augustine, Albertus, and Aquinas, who thus had to combat no one.
It is again Russell who reminds us that a serious text like that of F. S. Marvin appearing in Studies in the History and in the Method of Sciences repeats that “Ptolemy’s maps … were forgotten in the West for a thousand years” and that a manual of 1988 (A. Holt-Jensen’s Geography: Its History and Concepts) states that the medieval Church taught that the earth was a flat disk with Jerusalem at its center. Even Daniel Boorstin, in his popular book The Discoverers, says that from the fourth to the fourteenth century Christianity had suppressed the notion of the earth’s being round.4
From Constantine to Prester John
Another falsehood that changed world history? The Donation of Constantine. Today, thanks to Lorenzo Valla, we know that the Donation was not authentic. And yet, without that document, without a profound belief in its authenticity, European history would have followed a different course: no conflict over investitures, no mortal struggle for the Holy Roman Empire, no temporal power of the popes, no slap at Agnani, but also no Sistine Chapel, which was created after the Donation was called into question but could still be constructed because for centuries the Donation continued to be thought genuine.
In the second half of the twelfth century a letter arrived in the West, telling how in the far-off East, beyond the regions occupied by the Mussulmen, beyond those lands the crusaders had tried to wrest from the dominion of the infidel only to see them returned to that same rule, there was a flourishing Christian region, governed by a legendary priest John, or Presbyter Johannes, or Prester John, re potentia et virtute dei et domini nostri Iesu Christi. The letter began by saying:
know and believe firmly that I, Priest John, am lord of lords; and in every wealth that exists beneath the sky, as also in strength and power I surpass
