August 25: Happy Birthday, Galileo’s Telescope!
Was Galileo ultimately right?
If you like reading about philosophy, here's a free, weekly newsletter with articles just like this one: Send it to me!
The noblemen of Venice
Are telescopes born? Do they have birthdays? Certainly, there is a sense in which an instrument can come to life: when people look through it, use it, measure their world with it. When the members of the Senate of Venice lined up behind that middle-aged professor on that evening of August 25, 1609, eager to see the distances in front of their eyes shrink to nothing as if by magic, they were bringing a new thing to life: a concept, a tool, a new understanding of the stars, but also a weapon.
We have a record of that demonstration. How the nobles slowly scaled the bell tower of St Mark’s, finally standing at the top, the view open to the four directions of the compass. How Galileo pointed the telescope first to Padua, thirty-five miles away, so that all could see that city’s church towers. Then to Murano, where one could see little figures entering the church of San Giacomo. They turned the telescope to the sea and saw ships that would be invisible to the naked eye for another two hours. [1]
It is interesting that the first public presentation of the new technology wasn’t to the public, or to Galileo’s colleagues, to the other scientists. He first went straight to the politicians in the Senate. He was rewarded: they arranged a new professorship in Padua for him and a handsome yearly pension.
Image from a fresco by Giuseppe Bertini (1825–1898). Public domain.
Galileo didn’t invent the telescope, but, in a suicidal move typical for an absent-minded scientist, he had the idea to turn it toward the night sky. One can hear the Venetian nobles groan across the centuries:
Here is this professor who created the perfect tactical weapon: an instrument that can see in the far distance without being seen. Enemy ships! Approaching armies! We can spy on our enemies. From every church tower, we can see into the offices of lawyers and politicians and read their lips through glass. We can read their most secret documents, left lying on tables close to the windows. We can see exactly who walked through the church door in Padua today, without even being there! Surveillance! We can follow any citizen on his way through town, lip-read every conversation, see his every gesture, just by standing up here, pointing this magic metal tube at the distant figures. And what does the professor talk about? For goodness sake: all that he wants is to turn the thing away from everything interesting and look at the birds, the clouds and the stars… And, of course, God, who’s also somewhere up there, invisible like a distant ship on the Adriatic sea. Will we also see Him through that thing? And what good will that do us?
From the moment of this first demonstration of his telescope, Galileo was caught in a web of competing interests that would ruin his life and cement his fame at the same time. For the philosopher, there’s a series of interesting questions right there.
Can we control science?
For example, what is the relation of science and technology to society?
There are different answers to that. One could think that it is the scientists who create something new and then this new thing becomes a technology, and society has no choice but to accept it. This has been called technological determinism.
Sometimes it works like that. But here it doesn’t seem to. The telescope existed before Galileo used it, but actually it was not a product of science. Optics wouldn’t be able to explain for a very long time why the telescope worked as it did. Lens making was not a domain of science, but of artisanal craft. It was positioned so low in the hierarchy of occupations that even Jews, otherwise suspiciously eyed and socially sidelined, were allowed to be lens grinders (the philosopher Spinoza was perhaps the most famous of them).
So Galileo didn’t actually perform any science by looking through the telescope. He was using a tool that was already around, but one that was poorly understood. He showed off its usefulness to the members of the Senate of Venice. But then he left it at that. There was no move of the telescope industry to create a demand for the thing, there was no pressure or lobbying for society to adopt telescopes. Some of the senators surely saw what they could do with that thing, and they rewarded Galileo. But he wasn’t really interested. He went off to his lab and turned it toward the sky instead, bringing the wrath of the church upon himself.
![This image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence by the Board of Trustees of the Science Museum [2].](image1.webp)
This image is released under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence by the Board of Trustees of the Science Museum [2].
Was Galileo right?
Today it’s fashionable to see Galileo as a hero and the church as the evil oppressor of scientific progress. But that isn’t the full truth. Paul Feyerabend, famous philosopher of science, pointed out that Galileo wasn’t doing very good science when he used his telescope to look at the stars. He didn’t have a theory of how the telescope worked, and it wasn’t even established that one could use it to look at the sky in the same way as one looks at terrestrial things. To assume that the sky is just full of the same kinds of things as the Earth, and that the laws of physics apply to both domains in the same way, is already begging the question.
Also, Galileo didn’t perform single, simple experiments that proved clearly understandable points about his theories. It seems that he had undertaken many experiments in many different areas of physics and astronomy over his life, and that his interpretations about what he really saw in the telescope depended on many previous conclusions he had reached. So that he wouldn’t have been able to explain to an outsider why precisely seeing a particular thing in the telescope did indeed support his own view rather than the Ptolemaic view of the church that put the Earth into the centre of the universe.
So if Galileo was right in the end, it was more because he happened to be right, rather than due to his being such a great scientist. In terms of science, the Ptolemaic view of the world was more solid, better understood, and better supported by experiments than the crazy new ideas of Galileo. Galileo didn’t reach his conclusions by careful application of scientific principles, but by ignoring these principles and upsetting the science of his time; perhaps in a move similar to a modern researcher who would go off performing experiments to prove that homeopathy works.
Photo by Jaredd Craig on Unsplash
And this brings us back to the beginning of this article. Being right is a relative thing. “Right” in relation to what? One can be right in relation to the science of one’s times (like the church was), and wrong in an objective way. Or one can be right objectively (like Galileo) but wrong as far as good, solid science is concerned. One can be right for the wrong reasons, or wrong for the right reasons. And one can be right in an abstract, theoretical way, but wrong about the consequences of one’s insights. Galileo failed to see all the power that might have come from employing the telescope as a tool for war or surveillance, concentrating instead on a crazy, unproven idea about the relative positions of movements of the Earth and the Sun — and in doing so, he destroyed his own career and life.
To be “right,” unfortunately, doesn’t always mean that one is doing the right thing.
Happy Birthday, Galileo’s telescope!
[1] Description details from: James Reston, Galileo: A Life. Beard Books, 2000. Cited after worldhistoryproject.org/1609/8/21/galileo-demonstrates-his-telescope-to-venetian-lawmakers#.
