Monday, November 20, 2006

Who Refused to Look through Galileo's Telescope?

According to popular legend, when Galileo presented his telescope to senior cardinals/Jesuits/Aristotelian philosophers/the Inquisition (delete as applicable) they refused to even look through it. This tale has become a standard trope for when we want to attack anyone who won't accept 'obvious' evidence. As the last chapter of my book will be on Galileo, I thought I should try to nail down the primary sources for the legend. So I asked the internet's resident Galileo expert, Paul Newall of the Galilean Library to chase them down for me. His reply was extremely interesting.

There are three peices of evidence that have gone into the construction of the legend, as far as we can tell. The first concerns Cesare Cremonini, a good friend of Galileo and a Professor of Aristotelian Philosophy at the University of Padua. Quoted in a letter from a mutual friend to Galileo, Cremonini says of the telescope "I do not wish to approve of claims about which I do not have any knowledge, and about things which I have not seen .. and then to observe through those glasses gives me a headache. Enough! I do not want to hear anything more about this." It's clear that Cremonini did look through the telescope long enough to give himself a headache but could not see what Galileo could. Frankly, it was more than Cremonini's job was worth to endorse Galileo because it would have refuted Aristotle.

The second case is Guilio Libri, Professor of Aristotelian Philosophy at Pisa and no friend of Galileo's. He died very shortly after the telescopic discoveries were made public. Galileo was viciously biting when he heard the news, writing to a friend to ask if Libri, "never having wanted to see [the moons of Jupiter] on Earth, perhaps he'll see them on the way to heaven?" Did Libri refuse to look through the telescope or look and not see the moons (which was not easy at all, especially if you were old and without the keenest of eyesight)?

Finally, the senior Jesuit astronomer Christopher Clavius said of the moons of Jupiter "One would first have to built a spyglass that creates them and only then would it show them." However, the fault was with the Jesuits' first effort to built a telescope. Once they had built themselves a better one, Clavius confirmed that he could see the moons.

So who refused to look through Galileo's telescope? According to the historical record, no one did for certain. The argument was over what they could see once they once they did look.

Comments or questions? Post them at Bede's dedicated yahoo group.


- said...

You are correct - Refusal-To-Look - is used today as a figure of speech - and you did hit the nail on the head when you said that obvious evidences are often refused to be seen.

This is especially true when it comes to the vast distances as measured across our universe and the accompanying modern data gathered for a very old universe. Over the past decade using modern technologies (not even imagined in Galileo's day), we see stars in various burning stages - some being born, some (like our sun) in a very stable mid-life, others dying, some dead, etc. We see background radiation, an expanded and still expanding universe, galactic collisions, red-shifted light and a mountain of other data for which limited space here restricts, all pointing to an old universe.

Yet, is not the vehement denial of such data by many fine Christian brothers akin to a refusal to look because of an adopted orthodox view of creation superimposed upon God's handiwork of which we are directed to consider.

As so, are we not today still refusing to look - - ?

Anonymous said...

The point is that Galileo was willing to look further -- beyond what was commonly accepted. His insight was based on observation which is the fundamental basis of all science and knowledge to this day.

Cremonini(sp) insisted that all of the orbs must be perfectly round and smooth. Galileo saw through his invention -- the telescope, that the moon had peaks and valleys.

Legend says that Cremonini then said that "thats fine, but there is certainly a layer of ice taller than those mountains that make it perfectly smooth as Aristotle says"

The point is -- who was right? History will always tell who was correct.

Ever heard of Galileo?
Ever heard of Cremonini?

That's what I thought

Frankie said...

"The point is that Galileo was willing to look further -- beyond what was commonly accepted. "

True. Too bad his argumentation was poor. So poor in fact, that he didn't even follow his own data.

"The point is -- who was right? History will always tell who was correct.

Ever heard of Galileo?
Ever heard of Cremonini?"

Ever heard of Kepler? You know, the man who actually proved Heliocentrism? The man whose brass was actually backed up by solid data?

Unknown said...

Everyone will have a chance to look through Galileo's Telescope. This time, it is not at planets and moons. The most exciting 'Copernican Revolution' of our time will shock the world; this time it is turned inward toward us. Will you be willing to look?

Anonymous said...

I may be a bit late here, but I am also currently looking up on the veracity of this story. And I have found at least two quotes so far, reportedly by Galileo, in a letter to Kepler, that appear to suggest the story is true:

"Oh, my dear Kepler how I wish that we could have one hearty laugh together. Here, at Padua, is the principal professor of philosophy, whom I have repeatedly and urgently requested to look at the moon and planets through my glass, which he pertinaciously refuses to do. Why are you not here? what shouts of laughter we should have at this glorious folly! and to hear the professor of philosophy at Pisa labouring before the grand duke with logical arguments, as if with magical incantations, to charm the new planets out of the sky." (The life of Galileo Galilei: with illustrations of the advancement of experimental philosophy, by Bethune, John Elliot Drinkwater, 1830, page 29) (e-book:

and from wikiquote (

"My dear Kepler, what would you say of the learned here, who, replete with the pertinacity of the asp, have steadfastly refused to cast a glance through the telescope? What shall we make of this? Shall we laugh, or shall we cry? - Letter to Johannes Kepler (1610), as quoted in The Crime of Galileo (1955) by Giorgio De Santillana"

James said...

Thanks Anon. You can actually see the context of the Santillana quote by searching for "My Dead Kepler" in the look inside feature. It is not footnoted. Nor do we have a source from Drinkwater. Galileo's letters are published and easily referenced but somehow this quotation never is.

I think Thony Christie has also debunked the story here:

Best wishes


Julio Michael Stern said...

I find the references above very interesting. They point to crucial points in Epistemology and Philosophy of Science. Post-hoc judgments are always easy. However, it is far from trivial to give general rules (demarcation criteria) to accept or reject new theories, or even to judge the quality of scientific data or to validate new instrumentation.
Although very interesting, the references above are not sufficient for academic use. Could you please: (a) Give us precise quotations from the original documents (in Latin or Italian); (b) The corresponding references to the original documents; (c) Links to PDF scans of the original letters by Galileo and his correspondents? Thank you very much, J.M. Stern

Στέργιος Κατσογιάννης said...

This story only means that looking is not the same as seeing!

Karl said...

Hi James,

This is an old post, but the web never forgets, and others might stumble by late, like me.

Concerning the letter from Galileo to Kepler the 19 of August 1610. If I understand your reply to Anonymous correctly, you seem to imply that possibly the letter is fake or the translation is wrong. I did find the letter among the collected correspondence of Kepler, chapter 16 ( With the reference to the original: Wien, Nationalbibliothek, Cod. 10702, Bl. 65-66. Eigenhandig

Unless investigations in the Wien Nationalbibliothek shows differently, I suggest we should accept the letter, and the translated content, reported by Anonymous, as real and correct.

It didn’t take long looking inside the google telescope to find these information’s ;)

Best regards

Refractor Telescopes said...

Wow, it is a type of post that is not found in many places, the only "complaint" that I would put is that you did not indicate the dates of the possible events (already occurred): 1609 for instance.