‘vapours’, or an atmosphere, surround the Moon and planets, like
the Earth.45
In his 1584 book on Worlds, Giordano Bruno had written about
‘the Moon (which is another Earth)’, consisting of earth, water, air
and fire, as well as seas, rocks, mountains and valleys. 46 Likewise, in 1585, Bruno referred to the Moon ‘which we regard as another
Earth’.47 In his book Galileo now pondered whether his telescopic discoveries seemed ‘to revive the old Pythagorean opinion that the
Moon is like another Earth’.48
Like Bruno, Galileo did not attribute the notion of other worlds
to Democritus, crediting instead the Pythagoreans, as ‘Plutarch’ did
in his Placita. Galileo wrote that someone pursuing this view might
well interpret the Moon’s bright areas as land, and its dark areas as
bodies of water. Moreover, Bruno had claimed that the Moon was
allegedly the world closest to the Earth and similar to the Earth.
Bruno had even referred to the Moon’s inhabitants.49
Now, without mentioning Bruno at all, anywhere, Galileo
announced that the Moon really does resemble the Earth. But this
was a dangerous thesis for a Catholic. The Roman Inquisition had
censured and condemned Bruno for obstinately insisting that other
worlds exist.
Furthermore, Galileo declared that he would publish another
book in which he would ‘prove’ that the Earth moves, by ‘using
countless arguments’ from natural phenomena. He endorsed the
Suncentred theory that he attributed to the Pythagoreans. 50 But 110
Aliens on the Moon?
Galileo Galilei
discussing
his telescopic
discoveries. Etching
by Stefano della
Bella, 1656.
previously the consultors of the Inquisition had censured Bruno’s
Pythagorean belief that the Earth moves. Copernicus had claimed
that the Earth moves, but Galileo’s findings also seemed to confirm
Bruno, who said not only that the Earth moves, but put forward
other claims that Copernicus did not make: there are innumerable
stars, multiple moons, and our Moon has mountains, valleys and an
atmosphere.
In March 1610 Johann Wackher, counsellor to the Emperor, visited his friend Kepler to tell him, excitedly, that at Padua, using two lenses, Galileo had discovered four new planets. Kepler recalled:
Wackher told me the story from his carriage in front of my
house. Intense astonishment seized me while I listened to
this strange account. I felt moved in my deepest being . . .
[Wackher] was full of joy and feverish excitement, I with
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shame, at one moment we both laughed at our confusion,
the next [moment] he continued his narrative and I listened
intently – there was no end to it.51
Wackher was a Catholic convert, yet he had sympathized with
Bruno and he believed in particular that the stars are suns. Hence
Wackher imagined that Galileo had discovered planets that orbit
the stars. But Kepler disagreed. He rejected Bruno’s claim that stars
are suns, and believed instead that the one Sun is the centre of the
universe. Kepler also rejected the idea that the newly discovered
planets might orbit the Sun, because he thought that there could
be only six planets, which were separated by the five regular solids.
Therefore Kepler imagined instead that the new heavenly bodies
were actually moons orbiting some of the known planets.
Soon Kepler read Galileo’s book. He then met with Martin
Hasdale, who reported their conversation to Galileo in a letter. He
said that Kepler told him that the book truly showed the divinity
of Galileo’s intelligence, but that it led Kepler to resent Galileo’s
country for ‘not having made any mention of the authors who had
discussed and given occasion to investigate what you have now
found, namely Giordano Bruno, Copernicus, and himself [Kepler],
professing to have discussed similar things . . . ’.52 Notice that Bruno was mentioned before Copernicus.
Then Kepler penned a public reply to Galileo to promptly
remedy such omissions. Kepler finished his booklet, Discussion with
the Starry Messenger, on 19 April 1610. It is very significant because
it allows us to see how the leading expert in mathematical astronomy immediately responded to Galileo’s findings. Did he mention Pythagoras? Did he relate Galileo’s discoveries to Bruno’s ideas?
Interestingly, in this work Kepler mentioned Pythagoras six times,
he mentioned Copernicus seven times, while he named Bruno more
than either of them: eleven times. In Catholic countries it was considered inappropriate to refer to heretics, but Kepler spoke freely from Prague. He said that Bruno was ‘the defender of infinity’ and
had often spoken with the voice of Apollo.
Echoing his own book of 1596, Kepler discussed ‘the miracle
of Pythagoras, Plato, Euclid’, that the world could not have been
constructed differently from how God made it, using the five regular bodies. Kepler said that ‘Pythagoras interspersed the figures 112
Aliens on the Moon?
among the planets.’53 But now Kepler discussed the discovery of
‘new planets’ that he had pondered, he said, ‘for a long time from
the speculations of the Cardinal of Cusa and Giordano Bruno’. He
anticipated that since there were four previously unseen planets,
‘what would prevent there being innumerably many others?’
Kepler acknowledged that Bruno had considered infinitely many
worlds. Kepler even referred to his friend Edmund Bruce: ‘recently,
Bruno and Bruce – your friend, Galileo, and mine – envisioned
infinite other worlds (or Earths, said Bruno) similar to ours.’54
Kepler explained that according to Bruno the fiery stars had to be
surrounded by watery Earths, as a law of nature. But Kepler rejected
these ideas. It disturbed him to think that stars might be suns, surrounded by inhabited worlds. Still, he praised Galileo ‘for improving the doctrines borrowed from Bruno’. 55 This statement is very important for emphasizing the apparent continuity between the works of Bruno and Galileo. That is, it was very apparent to readers at the time,
even though many historians have neglected this point. 56
Like Bruno, Kepler described the Sun as a living being, and ‘as
the origin of life and motion in the world’. Kepler said that Galileo’s
telescope might eventually reveal more hidden planets, ‘that is, using
Bruno’s words, those being Suns, these Moons or Earths’.57 But
presently Kepler was relieved to find that Galileo’s four new ‘planets’
did not orbit the stars or the Sun, but instead were satellites orbiting Jupiter. He noted that, according to Bruno, Jupiter was another Earth and he publicly commented to Galileo: ‘If you could find
planets around the fixed speakers [ discursitantes: stars], then I am
ready for chains and prison with Bruno’s innumerabilities, or rather,
being exiled in the infinite. ’58 He thanked Galileo for freeing him of that fear.
Still, Kepler was fascinated by the similarities between the
Earth and the Moon. Galileo had asked whether his observations
might seem ‘to revive the ancient Pythagorean opinion that the
Moon is like another Earth’. Kepler noted that Galileo’s assertions
might seem ‘temerarious’. Yet Kepler brashly expanded them. He
explained that ‘following Pythagoras and Plutarch’ he himself since
1593 had written about ‘living creatures on the Moon’. From Galileo’s
descriptions of the Moon’s topography, Kepler inferred that indeed
certain beings live on the Moon! Kepler speculated that such inhabitants had large bodies and that they built barriers of clay to protect 113
burned alive
themselves from the insufferable heat from the Sun.59 Kepler argued that it was not improbable that Jupiter too had inhabitants.
To give evidence that the Moon does have an atmosphere and
moisture, Kepler cited a 1606 booklet (now lost) by his teacher
Michael Maestlin, who had reported having observed the Moon
during an eclipse in 1605 and seeing something remarkable. Maestlin
said the Moon looked reddish but exhibited a dark spot: ‘Call it a
cloud, spreading over a great region, raining & laden with tempestuous showers; such as is not rarely seen from the largest mountain ridges to the lower valleys [on Earth]. ’60 Kepler wrote that Galileo had confirmed some of what had been ‘predicted’ by his predecessors:
Bruno, Bruce and Maestlin.
Soon after Kepler’s Discussion was published, a young Bohemian
astronomer, Martinus Horky, published a tract intended to refute
the claims of Galileo. Horky had tried to see the phenomena with
Galileo’s telescope but had failed and seen nothing. Horky’s critiques
were furious and agitated. He especially assaulted Galileo’s claim
that four planets orbit Jupiter. He denied their existence as utterly
ridiculous. He said that Democritus was laughable. Horky insisted
that there exists only one Sun and one Moon, not many. 61 He accused Galileo of being a fraud. In June 1610 the General Inquisitor
at Modena, Italy, approved Horky’s essay for publication, noting that
‘I find in it nothing contrary to the Catholic faith. ’62
Kepler surmised that since Horky had failed to see anything
with Galileo’s telescope, he just had poor eyesight. Soon someone
else published an essay critically discussing Horky’s objections. John
Wedderborn was a Scottish student in Padua who upheld Kepler’s
arguments for why Galileo’s report was credible, even if one had
not yet used a telescope. Wedderborn quoted Kepler’s claim that
‘If you could find planets around the fixed speakers [stars], then I
am ready for chains and prison with Bruno’s innumerabilities, or
rather, being exiled in the infinite.’ He distinguished Galileo from
Bruno by saying that one could not derive the existence of the four
new planets from Bruno’s works: ‘others have already said that new
planets can be found: certainly Bruce and Bruno, old wives’ tales, but
only Galileo could help us discover new planets. ’63
Galileo’s discoveries did not merely support the notion that
Earth is a planet orbiting the Sun. They immediately triggered associations to the controversial Pythagorean ideas of Bruno. Were the 114
Aliens on the Moon?
stars suns? Were they surrounded by countless other worlds? Were
those worlds inhabited? Was the universe infinite? Does it have a
soul? One way to demonstrate that the Earth really is a soulful being,
a rational animal, was to prove a startling and counterintuitive fact
– that it moves.
Campanella Imprisoned and Tortured
In 1611 a prisoner of the Inquisition wrote to Galileo enthusiastically praising the discoveries in Message from the Stars. Tommaso Campanella was a questionable advocate: an apostate monk and
astrologer who had been repeatedly accused by the Inquisition.
Before discussing Campanella’s views on Galileo, we should discuss his links to Pythagorean ideas and how he became a prisoner of the Inquisition.
At the age of fourteen, Campanella was so impressed by learning about Thomas Aquinas and Albertus Magnus that he joined the Dominican Order in Calabria, southern Italy. Campanella had been
baptized with the names Giovanni Domenico, but he now took the
name Tommaso in honour of Thomas Aquinas. He studied logic,
philosophy and classics, but became sceptical about Aristotle’s writings. On one occasion his professor of philosophy sent Campanella to debate with some Franciscans. Campanella performed so well
‘that everybody was charmed with him, and cried out that the genius
Telesio was transmigrated into him’. 64 Campanella had not heard of Bernardino Telesio before, but became curious to know more and
became impressed by his philosophy, which said that truth should
not be sought in authoritative books but by directly examining
empirical facts. 65 Campanella developed irreverent philosophical views on the basis of recent and ancient thinkers. Soon the young
Campanella debated an old Dominican professor, spontaneously and
so successfully that the professor reported him to the Inquisition, as
if Campanella had acquired his vast knowledge by magic.
Regardless, Campanella wrote his first book, Philosophy as
Demonstrated by the Senses, which he published in 1591.66 He systematically critiqued Aristotle’s natural philosophy and cosmology, while defending Telesio’s ideas. Above all, Campanella developed
the idea that the Sun’s heat is the primal and noble factor that gives
life to all beings and connects them. Campanella transcribed a long
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passage from 1492 in which Ficino had commented on claims by
Plotinus about the ‘Soul of the World’. 67 Campanella approvingly quoted how Ficino described the World Soul:
But it is a most subtle body, almost not a body, & almost
more soul. Or almost not soul and almost more body. Its
power is minimally earthly in nature, but more watery, plus
more airy, yet more fiery stellar than most. In degrees from
these measures, the quantities of stars have been produced
from the elements. But it vivifies everywhere, it is the proximate cause of all generation and motion, of which he says:
‘Spirit nourishes within’.
By its nature all is luminous and warm, and humid and
vivifying, from such endowments arise the higher qualities of
the soul. Most of this was imbibed by Apollonius of Tyana,
as testified by the Indian Iarchas in saying: ‘No one should
be surprised, O Apollonius, that you have gained the knowledge of divination, for holding so much ether in your soul.’68
Campanella was greatly impressed by the arguments of Plotinus
and Plato, which Ficino construed as essentially Pythagorean. These
same arguments, about the soul of the world and the Earth being an
animal, had deeply influenced another prisoner of the Inquisition,
Giordano Bruno. Bruno too construed them as Pythagorean, as he
dangerously interpreted the Holy Spirit as the soul of the universe,
as he explained to the Inquisitors, saying that this idea ‘entirely
conforms to the Pythagorean doctrine explained by Virgil in the
sixth [book] of the Aeneid ’.69
Unlike Bruno, Campanella did not identify the Holy Spirit with
the soul of the world. Campanella argued that Varro misidentified
God with the soul of the world. Instead, Campanella argued that
God created things by means of heat, as a vivifying breath
of warm
air.70 Telesio too had written a book about similar notions, titled That the Universal Animal is Governed by a Unique Soul Substance.
Telesio had written it by 1565 but he did not publish it during his
lifetime. His manuscript circulated in handwritten copies until it
was published in 1590, two years after his death.71
Like Bruno, Campanella became disillusioned with the monastic approach to knowledge. He had studied philosophy, science and 116
Aliens on the Moon?
prophecy. He became fascinated with deciphering God’s signs about
the future. In 1592 the Inquisition in Naples examined Campanella
because of his controversial ideas. Campanella then went to Rome,
Florence and Padua, where, incidentally, he briefly met young
Galileo in 1593. Someone, however, denounced Campanella to the
Inquisition again on suspicion of heresies, so he was once more
arrested in early 1594. The Inquisition transferred him to Rome,
where he was imprisoned at the same time as Bruno, although we
don’t know if they met. The prisons of the Inquisition were on the
south side of St Peter’s Square.
The Inquisitors accused Campanella of supporting heretical doctrines. They said he had authored The Three Impostors, which argued that the fathers of the three monotheistic religions were impostors.
Campanella defended himself, for one, by saying that that book was
published thirty years before his birth. 72 The Inquisitors interrogated Campanella about four serious accusations. One was that he published ‘a doctrine about the soul of the world, about living beings and objects, contrary to the fundamental dogmas taught by the Church’.73
Unlike Bruno, Campanella recanted or denied it. The Inquisition and
the Roman city government did not kill him, but still the Inquisitors
subjected him to torture, declared him guilty of ‘vehement suspicion
of heresy’, and forced him to make a public abjuration. In late 1597
they relocated him back to a Dominican convent in Calabria. In 1596
Telesio’s book about the soulful, ‘universal animal’ was placed on the
Index of Forbidden Books, ‘until expunged’.
Meanwhile, by reading astrological and prophetic texts,
Burned Alive: Bruno, Galileo and the Inquisition Page 15