“He that is giddy thinks the world turns round.” W. Shakespeare
Galileo’s insult to the Pope ended in a trial for disobedience (not heresy). Galileo was convicted and sentenced to house arrest. (If you want a good summary of the trial look for Stillman Drake’s book, Galileo’s Scientific Biography.) After his trial Galileo wrote another book called Dialogues Concerning Two New Sciences. In this book he explained the ideas he had developed about motion. The germ of these ideas is in many of his earlier writings but here he made the rules explicit. This book (published by Elsevier in Holland, no Catholic press being willing to touch Galileo) basically says that the force an object exerts depends upon how heavy it is and how fast it is moving. (Imagine swinging a yo-yo around. You don’t want to be hit by the swinging object, but under no circumstances is the yo-yo going to suddenly swing you.) Put plainly what this means is that very large objects like the sun do not rotate around very small objects like the earth. The forces involved forbid this. This is where Galileo made his deepest contribution to the understanding of the solar system. This is the idea that turned into Newton’s 2nd law of motion. This is where Brahe’s idea was utterly crushed.
Why didn’t Galileo start here? Why did he get caught up in the idea of the tides?
What Galileo was living with was this: he was going against what people saw with their own eyes when he insisted that the sun was not rising in the east and moving across the sky, but rather that the earth itself was turning. So he was not impressed by the idea that observationally, the moon caused the tides. He wasn’t going to accept it unless he understood why it worked. This is what I call the physics mistake. As it happens the earth does revolve around the sun in defiance of our senses and the moon is responsible for the tides just as our senses tell us. Whether or not we can explain something is not actually the final word on whether it it true.
Isaac Newton has an example of the physics “mistake” in his works. When he couldn’t explain something he attributed it to a special intervention from God, that is, a miracle had occurred to move from point A to point B. As far as I can tell this is the origin of the idea of the God of the Gaps. Laplace wrote about the ideas of Newton and extended them, explaining things Newton had not understood. The King of France asked Laplace why he didn’t invoke God to explain things and Laplace replied that he didn’t need that hypothesis. This has given rise to the idea that Laplace didn’t believe in God. But that isn’t what was going on. Laplace simply understood things that Newton had still found obscure. This was classic advancement of science not arguments about God. As Albert the Great said, we are trying to find out what processes God has already placed in the universe, not what he can do with miracles. And it turned out that God had placed a lot more than Newton thought.
Here are two more examples of the physics mistake. In the early 1900’s Alfred Wegener proposed the idea that continents move. He was laughed at for years while he went around collecting evidence for his idea. He had no clue as to the mechanism but a lot of ways to show that it must have happened. Ultimately in 1971 the fact of seafloor spreading was shown and geologists converted to continental motion, now called plate tectonics.
I took an introductory course in Geology in 1974 and the professor told us that he was still wrestling with accepting what he had done to a graduate student from India in 1965. The student believed wholeheartedly in continental drift which makes sense since India shows a lot more evidence of it than North America. However when this belief of his became clear his graduate committee immediately wrote him off and flunked him, sending him back to India in disgrace. A mere ten years later my professor knew that he had committed a great injustice.
Brother Guy Consolmagno has another example in his book about being a Vatican astronomer. In the 1980’s certain meteorites seemed to be from an asteroid. Many people said this was impossible. Then a way for such meteorites to reach the earth was discovered. This led to a maxim that says:
If something did happen, then it can (happen).
What difference does all this make? The idea I would like to impart is that scientists, even very good ones, can and do make mistakes. Their mistakes can arise from their best instincts, their greatest ideas carried to an extreme. These mistakes will often end up being fixed as the scientific process of inquiry proceeds. This does not mean that such a scientist is no good. It means that all ideas must be tested and thought about over and over.
Think of what a disaster the Church would have stored up for herself if she had proclaimed as dogma that the sun stood still, as Galileo asked her to do. The sun moves. It is flying around the universe in the spiral arm of a galaxy and dragging the solar system with it.
The Galileo mistake is to assume that the current scientific consensus is the truth and that the Catholic Church should get involved. The Catholic Church has always counseled that it isn’t easy to understand the Bible and that reading the Bible correctly takes training. By the same token it isn’t easy to read the book of Nature. Religious people should not choose sides in what is in fact a scientific debate (unless of course they are scientists themselves and are arguing AS Scientists) and suggest that people who believe differently are sinners.
The fact that there is “consensus” is possibly the worst sign we could have about what is true. There was consensus in Galileo’s time that the earth stood still. There was consensus in 1908 that Wegener was wrong about continents moving.
There have been several ice ages in the past millions of years. There has been warming and cooling on a global scale over all that time. Humanity had nothing to do with it. Before we decide that we are in a runaway cooling or warming trend we have a lot of material to understand.