B U R N E D A L I V E
alberto a. m artínez
BURNED ALIVE
giordano bruno,
galileo and
the inquisition
reaktion books
Published by
reaktion books ltd
Unit 32, Waterside
44–48 Wharf Road
London n1 7ux, uk
www.reaktionbooks.co.uk
First published 2018
Copyright © Alberto A. Martínez 2018
All rights reserved
No part of this publication may be reproduced, stored in a retrieval system,
or transmitted, in any form or by any means, electronic, mechanical,
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of the publishers
Printed and bound in Great Britain
by TJ International, Padstow, Cornwall
A catalogue record for this book is available from the British Library
isbn 978 1 78023 896 8
CONTENTS
Introduction 7
1 The Crimes of Giordano Bruno 14
Pythagoras and Copernicus 17 | The Moving Earth and the
Fugitive Friar 28 | Prisoner of the Inquisition 37 | Censured
Propositions in Bruno’s Books 47 | Fire and Smoke 70 | Why
the Romans Killed Bruno 77
2 Aliens on the Moon? 100
Kepler Announces Life in Other Worlds! 103 | Campanella
Imprisoned and Tortured 115 | Bellarmine and the Enemies
of Bruno 123 | Galileo in Danger 137
3 The Enemies of Galileo 161
Campanella Defends Galileo from Prison 171 | Galileo Defends
the Pythagorean Doctrines Again 179 | Inchofer Against the
New Pythagoreans 203 | No Life in Other Worlds, No Living
Earth 211 | Campanella’s Exile and Death 232
4 Worlds on the Moon and the Stars 238
How Heretical, Really? 239 | Bellarmine’s Innumerable Suns 247
Critiques after Galileo’s Death 251 | Conclusion 264
references 281
acknowledgements 329
photo acknowledgements 333
index 335
Men of Galilee, why do you stand gazing up at the sky?
Acts 1:11
I have indeed asserted 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.
Giordano Bruno to the Inquisition in Venice, 1592
INTRODUCTION
Most people know about Galileo. They know that he said
the Earth moves around the Sun. And they know that he
got in trouble with the Catholic Church for doing so. The
Roman Catholic Inquisition condemned old Galileo to surrender
his freedom for the rest of his life. Nowadays he is admired as a hero
in the history of science.
Fewer people know about Giordano Bruno. Years before Galileo,
Bruno too was put on trial by the Inquisitors. They imprisoned him
for almost eight years. Then they finally condemned him to what
was feared as the worst kind of punishment: the jailors gagged him,
tied him to a post in a public place in Rome, and set the pyre on fire
to broil and burn him alive.
Historians say that Giordano Bruno was not condemned for
his beliefs about astronomy or cosmology – unlike Galileo. Still,
Bruno is increasingly famous. He was featured in the remake of the
popular tv series Cosmos. Its first episode, which dedicated much
of its airtime to Giordano Bruno, aired in 2014 and was watched
by roughly seven million people in the u.s. The narrator, the astrophysicist Neil DeGrasse Tyson, said that Bruno risked his life by voicing his vision of the cosmos: ‘the penalty for doing so, in his
world, was the most vicious form of cruel and unusual punishment.’
Soon, many commentators complained that Cosmos had misrepresented Bruno by echoing the myth that the Inquisition killed him for his cosmological views.
This book shows, despite all expectations, that Giordano Bruno
really was burned alive for his beliefs about the universe. Bruno
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burned alive
argued that the Earth has a soul and that many worlds exist.
However, historians didn’t know that those beliefs were con sidered
heresies, that is, crimes against God, punishable by death. By inspecting books on heresies and Catholic law, I found that these beliefs were heretical long before Bruno advocated them. Bruno didn’t
know this, and neither did later science writers. Furthermore, this
book will show that these same censured beliefs were involved in
the Catholic opposition to Galileo.
For over a hundred years, people have wondered whether the
infamous trial of Galileo was connected to the Inquisition’s previous
trial against Bruno. This book will show that these trials were indeed
linked. Some of Galileo’s critics were annoyed that he seemed to
support Bruno’s ‘horrendous’ beliefs: that many worlds exist and that
the Earth moves because it has a soul.
Christians denounced such beliefs as ‘Pythagorean’. In ancient
times Pythagoras was allegedly the Greek author of the theory that
Earth is one of the stars and that it moves. But historians didn’t
know that for a thousand years prominent Christians demonized
Pythagoras and his disciples as deceptive sinners and false imitators
of Jesus Christ. This book will illuminate the Copernican Revolution
in that neglected context. Surprisingly, Bruno’s condemnation was
caused mainly by his obstinate defence of such beliefs: the existence
of many worlds and the soul of the world. Most importantly, this
book reveals an unpublished Latin manuscript in which Galileo’s
most critical judge, the author of the most negative reports used by
the Inquisition against him, censured Galileo and the Copernicans
for those same beliefs. The Inquisition condemned the Copernicans
as a heretical ‘sect’ of New Pythagoreans.
This story is about the roots of the notorious conflict between
science and Christianity. Actually, the two have not often opposed
one another. 1 In fact, Christianity has often sponsored and supported the sciences. But we still struggle to understand what exactly happened between Bruno, Galileo and the Church.
There is another reason, too, why this story needs to be told: the
Roman Inquisition won. Not only did it succeed in killing Bruno
and silencing Galileo, it also succeeded in preventing people from
knowing Bruno’s beliefs. To this day, more than four hundred years
after Bruno died, most scientists and teachers are unaware that
Giordano Bruno’s account of the universe was far more correct than
8
Introduction
the beliefs of Copernicus, Kepler and Galileo. To this day, scientists
don’t know that Bruno belongs among those famous men.
This is because the Inquisition banned and burned Bruno’s
books. The clergymen of the Index of Forbidden Books pro
hibited
all Catholics from reading, quoting, discussing or even mentioning any of Bruno’s beliefs. They were forbidden from even writing Bruno’s name. He was a heretic, and Catholics should not write
about heretics. Thus they buried his role in the history of astronomy
and cosmology.
But here’s what really happened. Like Copernicus, Bruno too
believed and argued that the Earth really does move, at a time
when hardly anyone else asserted this, and long before Galileo
and Kepler. Yet Copernicus, Kepler and Galileo wrongly claimed
that the Sun and the stars do not move. But Bruno rightly said
that they move. In 1613 Galileo realized that the Sun spins on its
axis, yet did not realize that it also really moves through space, as
Bruno expected.
Copernicus, Kepler and Galileo believed that the Sun is the
centre of the entire universe. But here too they were wrong. Instead,
Bruno rightly insisted that the Sun is not the centre, not at all. He
alone rightly explained that our universe has no centre. Copernicus,
Kepler and Galileo also believed that the stars were all arranged in
a spherical heaven, but that was another big mistake. Instead, Bruno
thoughtfully argued that the stars are distributed homogeneously
throughout a boundless, infinite space.
And Copernicus, Kepler and Galileo thought that the Sun is
not a star. To the contrary, Bruno rightly insisted that the Sun is a
star, all the stars are suns, and many of them are larger than our Sun.
He first published these claims in 1584. Only five decades later, in
1633, did Galileo briefly suggest that the stars are suns – in just one
phrase in the fictitious voice of one character in his Dialogue of the
Two Chief Systems of the World.
Copernicus, Galileo and Kepler mistakenly said that the orbits
and motions of the planets were circular. But in 1584 Bruno rightly
denied it, insisting that no heavenly motions are real y circular. Only
35 years later did Kepler realize and prove that the orbits of planets
are not really circular. Galileo apparently never agreed with Bruno’s
or Kepler’s claims that the orbits were not circular. He mistakenly
argued that all natural motions are circular.
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burned alive
Next, in 1584, Bruno rightly anticipated that the Moon has
mountains and valleys. Copernicus, Kepler and Galileo published
no such prediction or claim: yet by 1610 Galileo confirmed with his
telescope that there are mountains and valleys on the Moon.
In 1584, and frequently thereafter, Bruno claimed that ‘innumerably many stars’ exist, stars never seen before. Copernicus, Kepler and Galileo made no such claim or prediction. By 1610 Galileo, with
his telescope, detected countless many stars that nobody in human
history had ever seen. He announced it on the title page of his book
as the discovery of ‘innumerable stars’.
Bruno argued that the stars are surrounded by planets that are
invisible to our eyes. Copernicus and Galileo made no such claim,
and Kepler even denied it. Yet again Bruno was right: four centuries later, in 1988, astronomers finally detected and confirmed the existence of a planet outside of our solar system. To date they
have found thousands of planets, just as Bruno expected. They are
now known as ‘exoplanets’. In May 2016 news articles reported that
astronomers had recently confirmed the existence of many more
Earthsized planets detected with a space telescope. It is ironic that
this telescope spacecraft, designed precisely to detect exoplanets, is
named Kepler, who actually denied the existence of exoplanets. It
should have been called the Bruno Telescope.
Next, Bruno also specified that some planets, other than the
Earth, are surrounded by moons. Copernicus, Kepler and Galileo
anticipated no such thing. Yet in 1610 Galileo discovered that,
indeed, there are moons orbiting Jupiter. Astronomers nowadays
expect that moons orbit exoplanets too, as Bruno said.
Furthermore, Bruno argued that planets are made of the same
elements as the Earth, that effectively they constitute other worlds.
Astrophysicists now know that indeed the planets are made of the
same elements as our world, in different proportions. And our spaceships have explored the surface of those worlds. Bruno proposed that heavenly bodies are surrounded by some kinds of atmospheres, like
the Earth. Again he was right.
Bruno even anticipated that humans might walk on and live on
such distant worlds, even on the closest one, our Moon. In contrast,
Copernicus made no such claim. Then in 1969, human beings travelled to the Moon and walked on it. Only after Bruno’s writings and Galileo’s lunar observations did Galileo consider that indeed some
10
Introduction
sort of living beings might possibly live on the Moon. But he wrote
very few words about this, and occasionally denied it.
When Galileo published a book in 1610, revealing his stunning,
telescopic discoveries – mountains on the Moon, satellites around
Jupiter and innumerable stars – such evidence did not confirm the
cosmological theory of Copernicus. Instead it confirmed Bruno’s
claims about the universe. Kepler pointed this out.
Bruno made some predictions that haven’t been confirmed. One
of them, which he made repeatedly, was that many alien beings live
on heavenly bodies other than the Earth. Today, many astronomers
and astrobiologists believe that this too is true, but they haven’t
yet found any clear evidence of such alien beings, despite countless
astronomic investigations. But when they finally do, they will prove
once again that Giordano Bruno was right.
It is no exaggeration to say that we don’t live in the cosy Suncentred universe of Copernicus. We live in the immense universe of Giordano Bruno. Who was this man who was right about so many
things? Why has he been so neglected and disdained in the history
of astronomy?
Scientists and historians who know about Bruno never make
the kind of accounting above. Instead they simply give Bruno a
plain dismissal: they say he wasn’t even a scientist. Why do scientists and teachers know so little about him? It is because of the longlasting consequence of Catholic censorship of Bruno’s works.
The Inquisition won. This book will discuss why Bruno’s beliefs
offended the Catholic clergymen so much and how such beliefs
were echoed later with hesitation by men who now are far more
famous: Kepler and Galileo.
But first, I should say a few things about my approach.
I focused on primary sources. I have also consulted scholarly
works that have been very helpful, but for brevity I have abstained
from long discussions of the extensive, valuable literature. Often
I give quotations from primary sources rather than paraphrase.
Having studied the evolution of myths in the history of sciences
and mathematics, I know how much meaning can change by omission or addition of a single word. So wherever I see an interesting paraphrase in a book or article I immediately wonder: what does
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burned alive
the original actually say? My preference for quotations reflects that
sentiment. In most cases I give my own translations from the originals, mainly from Italian, Latin, Greek, French and Spanish sources.
Regarding excerpts from poems and songs, I’ve translated each word
literally rather than retaining rhyme or metre by inventing phrases.
Writers make fascinating portrayals of the past, coloured by conjectures. However, I also appreciate the modest approach in which writers take great efforts to convey the past plainly, to say clearly
what happened, while trying not to get in the way, not to obstruct
through mediation. How much more would we value old sources
if instead of writers paraphrasing one another they had actually
used quotations? How much that is ambiguous would instead be
clear? In studying Bruno, for instance, I used secondary sources at
first. I was surprised by how much they disagree with one another.
Whenever a writer mentioned four or five Catholic accusations
against Bruno, I wondered how many others were there? How do
those few fit into the larger set? Only when I checked the primary
sources themselves did I realize that there were dozens of accusations. Yet to convey them all is very unusual. When one finds a secondary source that does so, then finally both the trees and the
forest become simultan eously visible. 2 Accordingly, I have worked to synthesize certain claims not just into paragraphs but to dissect
them as informative lists in which I have tried to be faithful to the
originals and to organize the evidence more clearly than in a paragraph format. Such lists convey how the most relevant particulars fit into the broad collection.
For centuries, people have interpreted the ideas of Pythagoras
and his followers in many different ways. In a previous book, The
Cult of Pythagoras, I showed how scholars have radically disagreed
in their interpretations. Some said that Pythagoras was a polytheist,
others that he believed in one God, or that he was an atheist. Others
said that he was a pantheist, or that he imitated Jewish doctrines, or
that he was a Buddhist, or that he believed in the Holy Trinity, and
so forth. Some writers say that Pythagoras was an aristocrat. For
others he was a poor, revolutionary exile. Others say that he was a
socialist, others that he was a communist, while others have argued
that he was an early pioneer of democratic thought. Owing to such
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