At the University of Padua
Wlodzimierz Redzioch talks to Prof. William Shea on the occasion of the International Year of Astronomy.
Mathematics is the alphabet with which God has created the universe. Fathoming the issue of the construction of the world is one of the biggest and noblest aims of man.
Wlodzimierz Redzioch: – 2009 is the Year of Astronomy. It is to commemorate the extraordinary event in the history of science – 400 years ago Galileo invented the telescope and made the first observations using this instrument. How was the telescope invented?
Prof. William Shea: – In June 1609 Galileo was in Venice where he met his friend who informed him that someone had managed to magnify objects. The scientist was very much interested in this invention and had the idea to connect two lenses: a concave one and a convex one (he had the highest quality lenses produced in the island of Murano next to Venice). He managed to magnify the picture of object twenty times! It was thanks to this wonderful instrument that Galileo could make his discoveries. That’s why the International Year of Astronomy is celebrated on the anniversary of the invention of the telescope.
– My outstanding countryman Nicolaus Copernicus claimed in 1543 that the Earth circled around the Sun – the heliocentric theory. Did Galileo approve the theory of Copernicus?
– Galileo was a supporter of Copernicus and using his telescope he proved the imperfection of the old system of Ptolemy, the so-called geocentric theory, and thus he strengthened the theory of the Polish astronomer. He wanted to find physical proofs for the movement of the Earth around the Sun. It seemed to him that such a proof could be inflows and outflows of seas, which according to Galileo must have resulted from the movement of the Earth around its own axis and around the Sun. This is a very interesting theory but it was false and nobody was convinced.
– Does it mean that Galileo did not have scientific evidence to support his thesis, which was Copernicus’ thesis? – Galileo had no convincing scientific proof.
– How did the conflict between Galileo and Urban VIII – his old friend, a very educated and open man, and the Inquisition begin?
– Galileo came to Rome in 1615 and he stayed there for six months. He wanted to present his theory there and had a series of lectures in the houses of outstanding Roman personalities. Finally, they began to wonder whether his theory was in accordance with the Bible. In 1616, the Holy Office (Sant’Uffizio) got interested in the whole matter and as a result, Copernicus’ work was put on the Index of Forbidden Books. However, it allowed the second edition of his book to be published under the condition that some sentences concerning the movement of the Earth were removed. The Holy Office wanted to present heliocentrism as a purely mathematical theory. It did not pass any sentence against Galileo. He was only warned by Cardinal Bellarmino [the Jesuit, eminent theologian, author of catechisms, doctor of the Church, canonised in 1931]. They wanted him not to teach his theory. Galileo obeyed this order to the time when his friend Cardinal Maffeo Barberini was elected to papacy and took the name Urban VIII. Then he published the book entitled ‘Dialogo sopra i due massimi sistemi’ [Dialogue Concerning the Two Chief Systems of the World], a truly literary and scientific work. However, the author made a big mistake. He put the opinion of Urban VIII in the mouth of some Simplicio, a silly boor who defended the geocentric system in the ‘Dialogue.’ Simplicio, i.e. the Pope, argued that we could get to know only what could be experimentally proved but since man could not fly into the space to make experiments there astronomy had to be a speculative discipline, i.e. based on abstractive thinking. No wonder, the Pope became irritated when he learnt about the book. Both Urban VIII and Galileo were proud and the conflict that happened after the publication of the book was of more personal than doctrinal character.
– We should not be surprised – both came from Tuscany and the Tuscans are known for their pride and hot temperament. Therefore, you call Galileo ‘troublesome genius’ in the title of your book. Was Galileo condemned only because he ‘incurred’ the irritation of the Pope?
– He was sentenced to stay at home because of purely ‘administrative’ reason– he was told not to teach Copernicus’ theory as a physical theory but he ignored that warning, hoping that nobody would learn about it.
– For ages the anti-Church propaganda has used ‘the trial of Galileo’ to demonise the Inquisition and to show the Church as an enemy of science and progress…
– The Church is not against science. Attacking it for that is pure propaganda!
– What did the trial of Galileo in Sant’Uffizio look like?
– Galileo was held under arrest for two weeks, from 12 to 30 April 1633. But he was not imprisoned. He lived in a three-room apartment and the cook of the Embassy of Florence delivered meals to the palace of the Holy Office. He could freely write and send letters. In a word, he was treated with respect as the mathematician of the Grand Duke of Tuscany. The hearings were conducted in the presence of only two people: the Dominican Vincenzo Maculano and his secretary Carl Sinceri. It was not a real trial but rather a discussion at the table.
– Why do all people claim that Galileo changed science?
– Galileo changed science thanks to his discoveries using the telescope. He discovered that the Moon was like the Earth, that there were spots on the Sun, that Jupiter had four satellites, that the Milky Way consisted of stars and some stars were bigger than one could imagine. Those things made way for a new vision of the world – the Church recognised that at once. Besides, Galileo stated that all objects, regardless of their weight, fall at the same rate. This was a revolutionary discovery that meant the end of the teaching of Aristotle and led to other discoveries, e.g. Newton’s discovery of the law of gravity.
– Let us come back to the instrumental use of Galileo, ‘victim of the obscurantist Church.’ Is it not astonishing that the contemporary agnostics, positivists and anti-clericals also show as a model of scientist the man who claimed that one should examine nature to discover ‘la mente di Dio’ (the mind of God) and pay homage to the Creator?
– Galileo was a believer but he did not practice his faith a lot. During his stay in Padua he did not attend Mass. But on the other hand, we know that he was a great worshipper of the Mother of God. He made at least two pilgrimages to the Marian sanctuary in Loreto. Like many of his contemporaries he thought that God gave man two books: the Bible and ‘the book of nature’ – both were necessary to get to know ‘ the mind of God.’
– What lesson should scientists and the Church take from Galileo’s trial?
– The conclusion is: we must read the Bible and ‘the book of nature’, realising that they have the same Author and consequently, these books cannot be contradictory. However, we should be cautious about interpreting the Bible because it teaches us how to get to heaven and not how the skies move.