First Parish Church - After Galileo

God and Scientists after Galileo

Charles A. Whitney
Professor emeritus of Astronomy, Harvard University

Presented in the panel
Galileo, Darwin, and God: Anniversary Retrospectives
First Parish Church in Weston
December 6, 2009

I will try to describe how Galileo forced a revolution in our thinking about the universe and its relation to Holy Scripture. He replaced the authoritarian science of Aristotle and the Ancients with a new kind of experimental activity that we call modern science.

This is the 68th anniversary of my first use of a telescope to look at the sky. As a teen-ager, I had a small telescope (about as long as my lower arm and similar to Galileo’s) and I spent many nights in my back yard looking at the stars and many of the same objects that Galileo examined 400 years ago: Jupiter’s moons, the craters on our own moon, and sunspots. The sky became an extension of my yard; it was as familiar as a playground.

But I had an epiphany in 1998, when my wife and I viewed a total eclipse of the sun from an island in the Caribbean. At the climax of the eclipse, I saw a black disc high overhead surrounded by pearly streamers of the solar atmosphere. It looked like a medallion on the dome of the sky. For a moment, and despite my astronomical background, I was awestruck and I felt as though I was standing on the floor of a great cathedral looking up into another world.

In that moment I not only understood, but also felt, the Ancient, Aristotelian, view that the earth beneath my feet and the heavens above my head were of two distinct domains: earthly and divine. Aristotle declared that the celestial was the domain of perfection and permanence. The earth is stationary at the center of everything, and the planets and sun and moon move about it on rotating spheres of heavenly crystal.

In Galileo’s time, the church fathers read Aristotle and they interpreted scriptural references to the heavens quite literally, even where Joshua asked the Lord to lengthen the day so he would have sufficient time to defeat his enemies:

… Joshua spoke to the Lord, and he said in the sight of Israel,
“Sun, stand still at Gideon, and Moon, in the valley of Aijalon.”
And the sun stood still, and the moon stopped, until the nation took vengeance on their enemies. (Joshua 10:12-13)

The church fathers interpreted this passage as implying that the sun is in motion about the earth—how else could it be asked to “stop”? And they saw this as a direct contradiction of the sun-centered hypothesis of Copernicus, published in 1543, in which the sun was stationary.

The preface to Copernicus’s book contains a disclaimer (inserted by a friend to protect Copernicus from the wrath of the Catholic Church) that the model was merely meant as a description and was not to be taken literally. But Galileo insisted on taking it literally and much of his life was devoted to the task of proving that Copernicus was right.

His telescope, about the size of a small baseball bat today, magnified by a factor of 30 the separation of any two objects in its field of view. This modest magnification turned out to be crucial, most of all because it permitted him to see Jupiter’s moons through the glare of the planet. He saw the system of Jupiter and its moons as an analogy to the sun and its planets—clear evidence that the earth might be traveling about the sun, as Copernicus proposed.

He also found the moon was more rugged than the earth, and spots blemished the sun’s face. All of these were evidence of the validity of Copernicus’s model and the falsity of the Ancient system.

His telescopic discoveries were published in a best seller, Starry Messenger (1610). The effect of this book was to do away with the ancient dichotomy between earth and heaven. He wrote as a devout believer, but he insisted that astronomy must be based on observations, measurements, and reasoning, rather than scripture.

He insisted there could be no disagreement between science and our interpretation of scripture, but he bluntly denied nature miracles. With characteristic wit he wrote,

“In my opinion, nothing occurs contrary to nature except the impossible, and that never occurs.”

He summarized his view by declaring that science is a study of the book of nature which is written in the language of mathematics. Many scientists have made such remarks and I think they meant to express their amazement at the success of mathematics in describing the behavior of the natural world.

His next book, Dialogs Concerning the Two Chief World Systems, brought the Inquisition onto his head. The Pope had earlier given him permission to publish a book on the universe, but Galileo was forbidden to discuss it at more than mere speculation. Galileo attempted to disguise his real purpose by writing it as a dialogue, but the resulting book grievously irritated the Pope.

There are several possible reasons for this irritation. In the first place, Galileo put the Church’s arguments in favor of Aristotle’s outmoded ideas into the mouth of a man called “Simplicio”. To the modern ear this sounds a bit like calling the Pope a “simpleton”, although in fact there had been a medieval writer with the name Simplicius of Cilicia (490–560 AD) who was well known for his uncritical writings about Aristotle. Another source of trouble may have come from the Jesuits, who had had a public conflict with Galileo on the nature of comets. In any case, the Jesuits evidently got the Pope’s ear and convinced him that Galileo’s book was an attack on the papacy and on him personally. Galileo was brought to trial for declaring that the earth moves, and for questioning the authority of the Bible.

At the end of the trial, he was forced to abjure his belief in the motion of the earth, and he was sentenced to a form of house arrest. This gave him the time and place to write one more great book on physics. He died in 1642, a year before Isaac Newton’s birth.

About 100 years later, the Vatican lifted the ban on his books. In 1992 Pope John Paul II declared that the church had been wrong in condemning Galileo, because it had failed to recognize the distinction between the scripture and its interpretation.

Scientists, being what they are, have ranged themselves all across the spectrum of beliefs in the matter of God. Newton, for example, was a devout theist who believed God arranged the universe. Newton could predict the motions of the planets, but he could not understand how the planets got into their remarkable flat arrangement in the fist place. So he closed this gap in his understanding by invoking God’s hand to set the starting conditions.

Laplace, on the other hand, thought he could understand the flatness of the solar system as a result of the rotation of a cloud of gas and dust from which the planets were formed. So he said he had no need of a god to start things off.

But, of course, he begs the question of where that cloud came from in the first place. Scientists cannot conceive something coming out of nothing, so once we have gone back to the Big Bang, we are stuck. Cosmologists now propose an unseen world of pure energy from which atoms have condensed.

But most of the universe is still invisible to us. What we are looking at is the tip of the cat’s tail, and we are all stuck when it comes to the question, “Why is there something instead of nothing?”

A truce has been declared between science and religion. Some writers have even declared a mutual dependence between them. Einstein said, “…science without religion is lame, religion without science is blind…. “

I am not sure that I agree, because I have seen a lot of science that is far from “lame” come from the pen of avowed atheists

Pope John Paul II put it more convincingly, I think, when he said, “Faith and reason are like two wings on which the human spirit rises to the contemplation of truth; Faith without reason withers into myth or superstition….”

Many of us have come to see the Holy Scriptures as a novelistic Book of Nature, written in the language of art if not mathematics.