(photo credit: Courtesy)
20, 1633, the Italian scientist Galileo Galilei is tried by the
Church for teaching that the Earth orbits the sun. As a result, on the Pope’s
order, he was confined to house arrest for the remainder of his life until his
death in 1642, at the age of 77.
One century earlier, Nicolaus Copernicus had published On
the Revolutions of the Celestial Spheres, the first book to outline a
comprehensive heliocentric cosmology. This revolutionary theory placed the sun
at center of the universe, rather than the Earth.
Geocentricism, the theory placing the Earth at the center of
the Universe, had been vastly accepted since the 2nd century AD,
when firmly established by Claudius Ptolemy.
What is known as the “Galileo affair” began in 1610 when he
came out against the Ptolemaic scientific view in his book Starry Messenger.
Using the new telescope he had developed, he made observations supporting
In reaction, many scientific and theological scholars
attacked the theory because it seemingly contradicted Ptolemy's model of the
universe, as well as several passages of Holy Scripture.
Galilei responded to that criticism in his letter to Kepler
in August 1610 saying “My dear Kepler, I wish that we might laugh at the
remarkable stupidity of the common herd. What do you have to say about the
principal philosophers of this academy who are filled with the stubbornness of
an asp and do not want to look at either the planets, the moon or the
telescope, even though I have freely and deliberately offered them the
opportunity a thousand times? Truly, just as the asp stops its ears, so do
these philosophers shut their eyes to the light of truth.”
While Church officials were willing to let heliocentrism be
taught as a hypothesis and discussed in scientific circles, the faith of the
ordinary people was to be safeguarded. However, Galilei argued that his
telescopic observations favored the Copernican heliocentric theory as a
As the Inquisition started taking serious notice of
Galilei’s work in 1615, he sent a letter to Grand Duchess Christina, which was
an essay on the relation between the revelations of the Bible and the new
discoveries then being made in science. His general stance was that the
relevant passages of the Bible, which he was accused of contradicting, should
not be interpreted literally, especially when taken from poetic or allegorical
By 1616, the attacks on Copernicus’ ideas had reached a peak,
to which Galilei responded by going to Rome in order to persuade the Catholic
Church authorities not to ban heliocentrism. Ultimately, the Inquisition
delivered him with an order not to "hold or defend" the idea that the
Earth moves and the Sun stands still at the centre. The decree did not prevent
Galileo from discussing the controversial subject.
Pope Urban VIII, elected in 1623, was a friend and supporter
of Galilei who opposed his condemnation in 1616. And thus, with the Pope’s formal
authorization along with that of the Inquisition, Galilei published Dialogue
Concerning the Two Chief World Systems in 1632. Previously, the Pope had
personally asked Galilei to give arguments for and against heliocentrism in the
book, and to be careful not to advocate the controversial theory. He also
requested that his own views on the matter be included in Galileo's book. Only
the latter of those requests was fulfilled by Galilei.
Whether unknowingly or deliberately, Simplicio, the defender
of the Geocentric view in the book, was often caught in his own errors and
sometimes came across as a fool. Indeed, although Galileo states in the preface
of his book that the character is named after a famous Aristotelian
philosopher, the name "Simplicio" in Italian also has the connotation
of "simpleton.” This portrayal of Simplicio made it appear as an
advocacy book: an attack on Aristotelian geocentrism and defence of the
Unfortunately for his relationship with the Pope, Galileo
put the words of Urban VIII into the mouth of Simplicio. Most historians agree
Galilei did not act out of malice and felt blindsided by the reaction to his
However, the Pope did not take the suspected public ridicule
lightly, nor the Copernican advocacy. Galileo had alienated one of his biggest
and most powerful supporters, the Pope, and was called to Rome to defend his writings.
With the loss of many of his defenders in Rome because of Dialogue Concerning the
Two Chief World Systems, Galilei was ordered to stand trial on suspicion of
heresy in 1633.
As a result, Galilei was found “vehemently suspect of
heresy” and was required to "abjure, curse and detest" those
opinions. He was sentenced to formal imprisonment at the pleasure of the
Inquisition. On the following day, this was commuted to house arrest, which he
remained under for the rest of his life.
Aside from his theoretical works, Galilei made several
contributions to “technology” such as an improved telescope, a thermometer, a military
compass and many many others. So great was his legacy that he was called by
Einstein the “father of modern science.”