an extremely wide range of interpretations, I decided to try not
to invent interpretations. History is full of fascinating events that
12
Introduction
actually happened, including many that have not been discussed, so
history doesn’t need my speculations. This is especially true in the
study of Galileo’s trial, which has generated a wealth of publications
that one scholar describes as ‘a vast secondary literature, prone to
identify speculation with fact . . . that gives us reason to recoil before
the torrents of rhetoric and floods of hypotheses which continue to
obscure the facts of the case’.3
So I have tried not to make unwarranted inferences. Finally,
please note that if I don’t specify something in an explicit sentence,
then I’m not trying to imply it. Books are structures that generate
meaning. The author doesn’t control al the meanings that sentences generate in each reader’s mind, which brings its own ideas and defin itions. But it’s a valuable interaction. I hope this book will
ignite lively discussions.
13
one
THE CRIMES OF
GIORDANO BRUNO
In 1616 the Inquisition in Rome ruled that Galileo Galilei should
immediately abandon the belief that the Earth moves around
the Sun.
An old and notorious Inquisitor, Cardinal Roberto Bellarmino,
now known as Bellarmine, officially warned Galileo that he could
no longer believe that, otherwise Galileo would go to prison. Right
then, the Index of Forbidden Books also denounced the theory that
the Earth moves, calling it ‘the false Pythagorean doctrine’. 1 Galileo too had credited it to the ancient philosopher Pythagoras.
Years earlier, in the 1590s, some of the same Inquisitors, including Cardinal Bellarmine, had interrogated Giordano Bruno, who was a prisoner of the Inquisition in Rome. And they censured his
belief in the Earth’s motion. Yet Bruno had boldly defended his
theory that the Earth moves because it is animated by a soul. To
his Inquisitors, he too called this belief ‘the Pythagorean doctrine’.
This is the missing link between the infamous trials of Bruno and
Galileo.
What a word: ‘Pythagorean’. Most people who write about
Galileo don’t even quote that word. But then we miss something.
Namely, that the ancient Greek man whom schoolteachers portray
as a famous mathematician, Pythagoras, was something else. He
lived in southern Italy, where he became a philosopher or a religious
leader. He died around five hundred years before Jesus of Nazareth
was born. And, actually, there is no evidence that Pythagoras did
what centuries later made him famous: there’s no evidence that
he proved anything in geometry. Instead, in ancient times most
14
The Crimes of Giordano Bruno
people knew him for other reasons. In particular, Christians viewed
Pythagoras as a pagan religious leader, a rival of Jesus Christ.
Reportedly, Pythagoras taught that when you die your soul travels
out of your body and is reborn in another. People also attributed
to Pythagoras strange beliefs about the Earth: that it is a heavenly
body and it moves.
The followers of Pythagoras were a scattered and mystical group.
They practised secrecy and silence, like a cult, and were bound by
oaths and ancient religious beliefs. For centuries curious philosophers sought the secrets of Pythagoras. In particular, Giordano Bruno praised ‘the School of Pythagoras’. Yet Catholics and Protestants
both excommunicated Bruno. Like a good Christian, Bruno wanted
to eat the host – the body of Christ. But they forbade him from doing
so. In 1592 the Inquisition arrested and imprisoned him in Venice.
He denied having believed any heresies and he defended himself as a
philosopher. But there were some beliefs that he refused to renounce,
beliefs about souls and many worlds: that there exist ‘infinite particular worlds similar to the Earth, which with Pythagoras I consider a star, similar to which is the Moon, other planets and other stars,
which are infinitely many’.
Bruno was also accused of having said blasphemies about Christ,
the Virgin Mary and more. The Pope and the Roman Inquisition proclaimed ‘all these propositions are heretical, and not now declared so for the first time, but by the most ancient Fathers of the Church and
the Apostolic Chair.’2 On a Thursday in February 1600, Giordano Bruno was burned alive. He was barely 52 years old.
Less than ten years later, Galileo used an innovative telescope to
look at the Moon. He made a sensational discovery: he saw mountains and val eys on the Moon. He pondered whether this was visual evidence ‘to revive the ancient Pythagorean opinion that the Moon is
like another Earth’.3 Perhaps now the Moon and the planets seemed to be not just luminous bodies, but other worlds?
But Galileo did not mention that the most vocal, recent advocate
of the theory that the heavenly bodies are worlds was a dead man
one should never name: the heretic Giordano Bruno.
There are mysteries here. What were the ancient ‘heretical propositions’ that the Inquisitors said were not original in Bruno but had been denounced by ‘the most ancient Fathers of the Church’ and
the Apostolic See?
15
burned alive
Likewise, in Galileo’s trial by the Inquisition in 1633 there is
the question: why were some Church officials so extremely upset
by the ‘false Pythagorean doctrine’ of the Earth’s motion? Even
Galileo’s former supporter Pope Urban viii became furious. The
Pope complained that Galileo ‘had dared entering where he should
not have, and into the most severe and dangerous matters that
could be stirred up at this time . . . matters, which involve great
harm to religion and more awful than were ever devised’. The Pope
denounced it as ‘the most perverse subject matter that one could
ever handle. ’4
But why?
Some Jesuits said that Galileo’s book of 1632 was ‘more harmful
to the Holy Church than the writings of Luther and Calvin’.5
But why?
The Catholic Church had lost half of Europe because of the
influence of Martin Luther and John Calvin. How could a scientific
question seem more dangerous than the deeds of Protestant heretics? How could the ‘Pythagorean doctrine’ of the Earth’s motion involve the ‘most perverse subject’ imaginable?
I think the problem was that the theory of the moving Earth
was associated with radical pagan heresies. I will link the trials of
Bruno and Galileo in a neglected historical context: the pagan
beliefs of the cult of Pythagoras. Historians know that the
Pythagoreans were a secretive religious group, yet there was no
historical account of how the Christians criticized their evolving
beliefs. How did this ancient religion relate to astronomy? How
did it clash with Christianity?
The Pythagorean thread is remarkable because it explicitly
shows up in the works of many important figures in the Copernican
Revolution, including Copernicus, Bruno, Kepler and Galileo. This
book will explain some wellknown events by setting them in the
context of others that are virtually unknown.
The cult of Pythagoras became notorious for antiChristian
beliefs: souls being reborn in many bodies, divination, many worlds,
many gods, the infinity and eternity of the universe, and denials
of the uniqueness of Jesus. The ‘false Pythagorean doctrine’ of the
Earth’s motion, censured by the Inquisition since the 1590s, was connected to heretical beliefs that had appeared in works on philosophy, magic and demonology for centuries.
16
The Crimes of Giordano Bruno
Occasionally a few historians have briefly sensed the implications of denouncing the Copernican theory as ‘Pythagorean’. For example, at the end of an article on Bruno, Jole Shackelford said:
The association of Copernicus’s ideas with the ancient central
fire cosmology of Pythagoras was more than a dismissal of
the antiquity of heliocentrism; it was especially damning,
inasmuch as it implied other shared heresies, such as the
Pythagorean belief in the transmigration of souls. Such
teachings were not to be tolerated in postTridentine Rome. 6
Still, investigators have not traced such implications until recently. 7
We will see that such heresies were of utmost importance in Bruno’s
deadly trial in the 1590s. Later, the Inquisition’s proceedings against
Galileo involve striking continuities.
Some historians have done valuable research on the history of
the belief in many worlds, throughout the centuries. 8 But now, the belief in many worlds will acquire a surprising, new importance
in understanding the Inqisition’s proceedings against Bruno and
Galileo. Because this belief was heretical. It was a crime against God.
Pythagoras and Copernicus
To understand the conflicts in the Renaissance, it is necessary to
first trace some earlier conflicts. Early Christian theologians, such
as Hippolytus, Chrysostom, Jerome and Augustine, had formulated
notions that were echoed much later by Catholic theologians. In the
times of Bruno and Galileo, such ancient notions were not forgotten.
On the contrary, those were the authoritative judgements that were
followed by the Inquisitors and the censors of the Index. Hence the
ancient theology is directly relevant to the later conflicts.
According to late accounts, Pythagoras was born on the Greek
island of Samos in the Aegean Sea, around 570 bce, and he became a
philosopher in southern Italy. Nowadays astronomers and historians
refer to Pythagoras as a forerunner of Copernicus, but this is actually
a mythical identity. There is no reliable evidence that Pythagoras was
an astronomer or even a mathematician.9 Nowadays, many school textbooks claim that Pythagoras was the first person to prove the
Pythagorean theorem: the square on the diagonal of a right triangle
17
burned alive
equals the sum of the squares on the other two sides. However,
ancient sources don’t say this. I have found no evidence that anyone
in antiquity claimed that Pythagoras proved the theorem.
The earliest such instance I have found is not from a century
or five after Pythagoras died, but from roughly two thousand years
after his death. In a work on Euclid’s Elements published in 1557, the
author Jacques Peletier commented about the hypotenuse theorem,
that ‘Pythagoras proved a general demonstration of it.’10 Thus similarly many other myths about Pythagoras’ alleged achievements in mathematics have arisen over time.
In addition to there being no writings by Pythagoras himself, the
extant texts of early Greek writers on mathematics or astronomy, by
Plato, Aristotle, Archimedes, Apollonius of Perga and many others,
make no claim whatsoever that Pythagoras worked on mathematics or astronomy. Various ancient writers mentioned him, including Heraclitus of Ephesus, Plato, Herodotus, Heraclides and Isocrates.
The sum of their various brief comments gives the impression that
Pythagoras was a wise man, a popular religious leader who argued
that the human soul is born repeatedly, even in animal bodies. It
seems he taught his followers to live in a disciplined way, including
some dietary restrictions, such as not eating beans or animals, at
least of certain kinds. His followers modified his teachings, sometimes creating opposite beliefs. Aristotle criticized ‘the socalled Pythagoreans’ for saying ‘that the Earth is one of the stars’ and that
it moves around a central fire. 11 Still, we have no claims by Aristotle about Pythagoras himself.
Pythagoras was most famous for allegedly teaching that human
souls can be repeatedly reborn, even in the bodies of animals.
According to some mythical accounts, Pythagoras was the son of a
god, either Apollo or Hermes.12 Allegedly, the soul of Pythagoras was originally born as Aethalides, and Hermes granted him the gift
of remembering his past experiences, even in future lives. His soul
was reborn in plants and animals, and even travelled to Hell. Later
he was reborn as the warrior Euphorbus, next as Hermotimus, followed by Pyrrhus the fisherman, and fifth as Pythagoras, who still remembered his past lives. 13 According to the poet Ovid, Pythagoras occasionally departed from the Earth and travelled to the stars.14
For more than a thousand years famous Christian theologians
vilified the Pythagoreans for sins and blasphemies. They complained
18
The Crimes of Giordano Bruno
that Pythagoras practised ‘ten thousand kinds of sorcery’. Some
of his followers said that Pythagoras was the son of a god and a
human mother. Whereas Jesus had died and resurrected only once,
Pythagoras had survived death multiple times. Allegedly his soul
had been reborn in other bodies. St Hippolytus of Rome ( d. c. 236
ce) criticized the ‘alliance between heresy and the Pythagorean philosophy’ and he denounced the ‘enormous and infinite heresies’ of the ‘disciples not of Christ but of Pythagoras’.
The cosmology of the Pythagoreans annoyed the Christians. The
Pythagoreans said that the infernal regions begin with the Milky
Way, from where souls fall to the Earth. Others said that human
souls come from the soul of the Earth. According to one book, al legedly by Plutarch, Pythagoras taught that, ‘when bodies die, souls join the soul of the world. ’15 Others said that the Earth is alive, that therefore it moves. Stars and planets were other worlds. They said
that souls live in those other worlds, and that there are demons living
on the Moon. They said that Pythagoras came from Jupiter and had
lived on the Moon as a demon.
Whereas Jesus had been dead for less than three days before
his resurrection, Pythagoras allegedly spent two centuries in Hell,
and yet returned to life. Diogenes cited claims that Pythagoras
was the god Apollo who spent 207 years in the underworld, and
saw all the men who ever died: ‘he saw the soul of Hesiod tied to
a column and gnashing its teeth; and that of Homer hanging from
a tree with serpents around it, as a punishment.’ Diogenes added
that Pluto, god of the dead, ate only with the Pythagoreans.16
Some said that Pythagoras taught that there exists not just one
God, but many.
Similar to the apostles of Jesus, some of the disciples of
Pythagoras allegedly resurrected the dead and exorcised demons.
But unlike the
apostles, allegedly some Pythagoreans even returned
to life after death.
The Church Fathers complained that all of this was indecent
madness, perverse falsehoods most deserving of ridicule, evil imitations of the miracles of Jesus. St John Chrysostom declared,
‘this is the snare of the Devil.’ Using magic and divination, the
Pythagoreans seemed to control nature and gain advice from
demons. The Christians complained that the Pythagoreans presumed to be equal to God. One of the admirers of Pythagoras, 19
burned alive
Porphyry, authored a scathing attack on Christianity, Fifteen Books
against the Christians. These books were banned by the first Christian
Roman emperor. There was extensive censorship, and the Christians
seized and burned the most offensive Pythagorean works until only
scattered quotations remained.
Because of his extensive, historicalcritical attacks, Porphyry
became known as one of the greatest enemies of Christianity. His
name became synonymous with blasphemy. St Augustine later
said that Porphyry hated Christ and was ‘the most bitter enemy’ of
the Christians. Augustine criticized Pythagoras as a necromancer
who tried to divine the future by contacting the dead, or demons
pretending to be gods.
Throughout the centuries the Christians rejected the ‘poisonous doctrines’, ‘devilish’ deceptions and perverse blasphemies of the Pythagoreans. And they declared, ‘Philosophers are the patriarchs
of the heretics. ’17
In 1244 Thomas Aquinas joined the Dominican order, which
had been recently founded to preach the Gospel and to combat
heresies. Thomas eventually became famous for authoring extensive
commentaries on scriptures and theology as well as on Aristotle’s
works. Thomas’s opinions became so authoritative that they were
held in the highest esteem not only by the Dominicans but by
other Catholic orders such as the Jesuits, founded in 1540. Hence
his judgements on Pythagorean topics are especially relevant.
In 1594 the Fifth General Congregation of the Jesuits issued
several rules requiring that their theologians and teachers should
follow St Thomas. The Jesuits explained:
by unanimous consent of all the deputies, it was decreed that
our professors must follow the doctrine of St Thomas . . .
Burned Alive: Bruno, Galileo and the Inquisition Page 2