One of the standard stories that gets wheeled out every time that some ahistorical fan of Galileo wishes to prove that the rejection of the heliocentric hypothesis at the beginning of the seventeenth century was purely based on dogmatic religious ignorance and had no objective basis in fact is the case of the professor of philosophy who refused to even look through Galileo’s telescope, rejecting his astronomical findings out of hand. Even if this story was true, as it stands in the simplistic version sketched above, it use in this context is questionable to say the least. Supporters of science contra pseudo-science, and they are the ones most likely to quote the story, have a mantra that in one version reads, “The plural of anecdote is not data”. They, quite rightly, reject the presentation of anecdotes as scientific evidence but are quite prepared to base their interpretation of the history of science on an anecdote; not exactly what one would call consistency. Even if twenty North Italian professors of philosophy had refused to look through Galileo’s telescope, rather than one, it would still tell us nothing about the epistemological status of the heliocentric hypothesis in 1610 or the grounds for its rejection by the majority of those qualified to judge. However the story has an even more interesting status as historical evidence because although true, it is, as usually related, a myth.
The standard version presents Galileo as the visionary apostle of modern science and the refusnik as a bigoted ignoramus. This picture is far from the truth; Galileo and his opponent in this case were best friends and the true story reveals several very important aspects of the early use of telescopes and the scientific problems that the first telescopic discoveries generated.
The professor in question was Cesare Cremonini (1550 – 1631) who was appointed to teach at the University of Padua shortly before Galileo and both of them belonged to the same clique of polymath, rebellious intellectuals in the Venetian State that include Paolo Sarpi amongst others. Cremonini was a hard-core supporter of the philosophy of Aristotle and thus Galileo’s natural opponent and the two indulged in good natured and usually humorous sparring matches, often for the entertainment of their mutual friends. Cremonini was also a permanent object of investigation of the Inquisition because he rejected the Church’s Thomist interpretation of Aristotle preferring his Peripatetic Philosophy pure. He was thought, following Aristotle, to believe in an eternal universe without creation and the mortality of the human soul, which did not endear him to the Church. Although radical in his views and highly argumentative he did not disparage his opponents, he wrote in his book on cosmology, De Caeolo (1613):
Disagreement about learned matters does not make enemies of honourable men, rather, it is a sign of great ignorance to dislike people who do not accept your opinion. [a dictum that many users of the Internet could take to heart]
In fact it was the writing of this book that led to the infamous telescopic rejection incident. A mutual friend, Gualdo, wrote to Galileo saying that Cremonini was planning on writing a book, De Caeolo, against him. Galileo replied feigning trepidation to which Cremonini responded that Galileo need not worry, as he wasn’t going to mention him or his discoveries in his book. It was within this exchange of friendly banter between three friends that Cremonini stated that he didn’t trust telescopes because when he looked through them they confused him and made him dizzy. He inferred that only people with quirky eyesight and unrestrained imagination could see what Galileo had claimed to see. It should be noted that it was well known that Galileo did indeed have ‘quirky’ eyesight.
Most authors retelling the story completely ignore the context and even ignore the fact that Cremonini had actually looked through telescopes and those that mention his claim that it made him dizzy do so as if Cremonini was trying to ridicule the telescope and its users. There is another more rational explanation, Cremonini was simply telling the truth.
The early telescopes were to put it mildly very primitive. They suffered from spherical and chromatic aberration, had a very narrow field of view and the glass out of which the lenses were made was of very poor quality often leading to extreme distortion of the images viewed. One early user described the stars that he saw as rectangular in form, very blurred and fringed with colours. It is actually highly probable that Cremonini genuinely had negative experiences using telescopes.
In his exchanges with Galileo Cremonini had another much more serious reason for rejecting Galileo’s telescopic discoveries. He argued, quite correctly, that if the moon was really a large lump of rock as Galileo claimed then he, Galileo, would have to develop a new physics to explain why the moon didn’t fall on the earth. He Cremonini would wait until that new physics existed before accepting Galileo’s discoveries. Galileo was of course very much aware of this central problem in his cosmology and in fact devoted most of his scientific activity in trying to solve it. As I have commented on more than one occasion on this blog this was in fact the central reason why heliocentricity could not be accepted until the end of the seventeenth century; a century that was scientifically devoted to creating that necessary new physics.
I think that what this comparatively trivial story from the early stages of the acceptance of a heliocentric world view teaches us is that often repeated simplistic stories from the history of science often take on a completely different meaning when told in full and in context.
 My version is based on that recounted by John L. Heilbron in his Galileo, OUP, 2010