William R. Shea is one of the world’s major experts on Galileo. He holds the Galileo Chair at the University of Padua, dedicated to the study of the great scientist, who himself taught at Padua for 18 years, from 1592 to 1610.

Shea comes from Cambridge, Harvard, and McGill University of Montreal; he was Director of the Institut d’Histoire de la Science at the Louis Pasteur University in Strasbourg, and is considered an absolute authority on everything regarding the history of modern scientific thought. On March 12th, on the occasion of the World Year of Astronomy declared by the United Nations, he came to the Milan Cultural Center to speak on the topic,“What Galileo’s skies proclaim,” in the course of the 400 years since the invention of his telescope. He spoke of that summer evening of 1609 when, from the Torre dei due Mori in Venice, the Pisan genius pointed to the skies with his new instrument, much more powerful than all those previously made, beginning a scientific revolution that was to move the earth from the center of the universe and to change even Christian culture.

Professor Shea does not believe, as do many of his colleagues, that Galileo was a victim of an anti-scientific Church. He does not like Galileo to be used as an icon to cite every time there are discussions (relating to moral issues, not to scientific method) between Catholics and non-Catholics. In his book (co-authored with Mariano Artigas), Galileo Observed: Science and the Politics of Belief, Shea recalls that the “Galileo case” was used by the Protestant Reformation as an anti-Papal weapon; he says that it needs to be re-examined, and not through the lens of late-Enlightenment polemics. If, thanks to Galileo, it is now clear that “theologians should not pronounce on the laws of nature,” he writes, it is just as true that “scientists should not expect religion to be tacked on to current speculative ideas about physics.”

“Galileo observed” professor. The important thing is to observe him with a certain detachment, even with a scientific coldness.
Exactly. We mustn’t make a myth of him; we have to go beyond this conflicting propaganda between secularists and curialists–and I don’t mean just Catholics. Some people want to make a “secular saint” of Galileo, as if he were untouchable. I am surprised at the attitudes of colleagues of my generation who are worried about what I write, not because it’s false–they are honest enough to admit it’s all true–but because they consider it inopportune.

What was Galileo’s greatness?
He had the good fortune to be able to exploit recent Italian technology: lenses of exceptional quality. In the month of July 1609, he went to Venice. His friend, Paolo Sarpi, told him that someone had found the way to magnify things using glass lenses. The lenses produced by the artisans of Murano were better than any other kind made in Europe. Toying with a concave lens and a convex one, Galileo managed to magnify an object first 6 times, then 9 times, and then as much as 25 times. It was an exceptional result, which others in Europe were to achieve only 20 years later. He didn’t understand exactly how that wonderful “toy” worked, but he had the great and quite original idea of pointing it to the sky, opening the way to a very important discovery.

But he didn’t use it only for scientific purposes.
If I can magnify objects 10 times, then with the telescope I can identify people at a distance; I can see an army advancing and can estimate its strength. On August 22, 1609, Galileo took his invention to Venice and showed the patricians the advantage of identifying ships at sea and distinguishing the kind of cannon inside a fortress. He was a man of great intelligence, but also a very cunning one.

Did he know how to move in politics?
He could handle money, but he was not cut out for politics.

When he returned from Padua to Tuscany, his life took a turn.
He became a courtier. In Florence, Galileo had to be the brightest, most intelligent intellectual, because this was what the Grand Duke of Tuscany expected of his official mathematician. In other words, he began another job, rather like today, when a good university professor goes into politics and immediately becomes dogmatic.

Success has its price…
He lost all sense of proportion. He treated his colleagues in Pisa unkindly, and scornfully. He used an irony bordering on hurtful caricature. Galileo did not joke much about himself, though.

As far as character goes, he was not an easy person. You defined him as “troublesome,” someone disturbing, a firebrand.
Galileo was a genius. On the psychological plane, though, he had a certain tendency to overrate himself. He was certainly a very fascinating man, but very hard on those who didn’t see things his way. This also explains why he was condemned. The real reasons remained rather mysterious to me until I read his correspondences. The whole of Pisa was quite happy to see him censured. Isn’t it strange? One would have expected some protest, or a letter of regret… There was none of this in the intellectual world around him.

In the relationship with Urban VIII, these elements had some weight.
Urban VIII, Maffeo Barberini, too, was a man convinced of his superiority. He considered himself, for example, the greatest Italian poet of his time, something absolutely to be excluded, experts tell me. He too was very arrogant. They were both Tuscans, by the way. There are some aspects of their relationship that bring a smile to one’s lips, though with Urban VIII, smiling could have been dangerous. Reading the Dialogue Concerning the Two Chief World Systems, the Pope can be seen represented in the figure of Simplicius.

He looks like a fool, as the name suggests…
And it made him very angry.

Why, exactly, was Galileo condemned?
He was warned not to teach the Copernican system as a physical theory. He thought that they would not find out because he taught it only to a few close friends. Naturally, though, in the Pontifical States, there were dossiers open on such important people, and they caught him.

John Paul II asked the Church to make amends for the “Galileo case.” As a scientist, what do you think of this choice?
It was a very interesting gesture, but things need to be reviewed against the historical background. The Church and science in 1600 were very different from what they are today. Even from the religious point of view, I think we need to talk of our present needs and not judge our predecessors with presumption. Certainly, we can learn from what happened in the past, but if, with our present-day awareness, we presume to condemn all that we didn’t do 400 years ago, the list of “sins” for all the religious confessions, and for all the secular states, too, would be very long… Galileo’s case has been exploited ideologically.

And he made some mistakes, too.
In science, more internal criticism is often needed, just as a moral authority like the Church needs more modesty and more of the Franciscan spirit, which were lacking then.

Has something new emerged since the Vatican archives were opened?
It’s a pity it was not decided earlier. Nothing new has come out. What has been discovered is precisely that there was nothing to discover, except some details of the Roman environment in those years. In the Vatican, they are very kind to us scholars. There is a Spanish monsignor who make everyone’s research easy, whatever his religious leaning.

You have also studied Pascal, Descartes, Newton, and Kepler: almost all these geniuses of modern science had great trust in human reason, but also faith in God.
There is no doubt. They were convinced that human rationality is founded on the rationality of Creation itself, and thus, by knowing–as Galileo says–the “book of Nature,” we can know something of the Mind of God. Since then, modern man has read the Bible in order to know the world of the will and of moral law, and has read Nature to know the “thoughts of the Creator.” You could write a book on religion as the motor of scientific revolution. The Judeo-Christian vision of a God who creates with intelligence has, without doubt, contributed to the development of modern science. Almost all its founders speak of God, and it is the God of Christian revelation.

Personally, was Galileo a Christian?
He didn’t read the Bible and he didn’t go to Church, or only rarely. He was a normal believer. However, he considered himself a Catholic, even though he would have considered himself a sinner, because he did not have an irreprehensible life. If we read his biography, we find he went on pilgrimage to Our Lady of Loreto, though he didn’t like walking at all, since he suffered from a double hernia, so it would have been quite an effort for him.

What idea did he have of God?
He never spoke of Christ–his is more “a God of Nature.” Galileo was never a great theologian. Thanks to recent studies, we know that for his reflections he depended on a group of Barnabite priests, a certain Baroncini, and the director of the convent in Pisa, Tartaglia–who had begun to interpret the Bible as a document of a spiritual nature, drawing ideas from the Fathers of the Church. Within the Catholic Church at that time, there was already an advanced reflection on these themes, and these were placed at Galileo’s disposal. More than an original thinker, he was a good “journalist.” He was able to present rather arid theological ideas in a vibrant way, using his grand prose. He was a very good writer, but there were people who had worked on these themes before him. As often happens in intellectual processes, Galileo provided wide diffusion to ideas that were not his.

You defined as naïve the idea that absolute scientific freedom leads “inevitably to a better world.” You have written that, in questions of a moral character, science cannot be the “last tribunal.”
Today, we have entered into a phase in our knowledge in which it becomes possible to interfere with the human person, modifying DNA and even the brain. I believe a reflection is necessary. We cannot alter man’s nature without reasoning over the possible consequences. It is a critical moment, in which the Church and other institutions can give their contribution, acting on a rational level, not a sentimental one. Naturally, I am speaking of a rationality that does not stop at technology–reason is a much broader faculty; it is the relationship between human beings and respect for freedom. These are themes that have to be tackled. The “Galileo case” is a call to caution, to be attentive to the complexity of the phenomena.

Why does the discussion go on and on?
There is still a tension between secularists and Catholics that sometimes seems strange to me. A “St. Galileo” has been created that does not correspond to historical reality; it is a fictitious idea. But apart from these polemics, I think many scientists have little knowledge of the Church.