By JUDE DOUGHERTY
Bucciantini, Massimo, Michele Camerota, and Franco Giudice. Galileo’s Telescope. Trans. Catherine Bolton. Cambridge, Mass.: Harvard University Press, 2016. x + 339 pp.
No, this is not another treatise on the “Trial of Galileo,” or l’affaire Galilée as Descartes called it. For those who are vaguely acquainted with the subject, this is a thriller as exciting as any that may have kept you spellbound. There are heroes and villains, and then there is Galileo.
When will he learn of the spyglass that caused such a stir when presented to Count Maurice of Nassau at The Hague? Will he ever acquire a specimen? Will he ever learn to build one himself? Will he ever acquire the lenses needed to perfect the instrument? And will he ever turn skyward the instrument designed for military use?
Such is the way the story unfolds as told by three historians of science whose narrative draws extensively on correspondence between aristocrats of the period. Call the book a social history of science, if you will. But it is foremost a history of the telescope.
The story begins when the Flemish craftsman Hans Lippershey visited The Hague early in 1608 to show Count Maurice of Nassau, commander of the Armed Forces of the United Provinces (of the Low Countries), “a certain device through which all things at a very great distance can be seen as if they were nearby.” Lippershey sought from the count a patent and financial support for the development of the instrument.
News of the invention spread rapidly, as evidenced in a painting by Jan Brueghel the Elder depicting Archduke Albert of Bavaria with the spyglass observing a distant castle. Clearly, in the words of one correspondent, “the act of seeing no longer coincided with our natural organ of sight.”
Within a few months specimens of the spyglass could be found not only at The Hague but in the Court of Henry IV in Paris, at the Court of Rudolf II in Prague, at the Court of the Spanish King in Madrid, at the Residence of General Albert Spinola in Genoa, and at the Papal Court of Paul V in Rome. And, we might add, in the halls of nobility in London, Augsburg, and Naples, as well. Remarkably, the ambassador of the Hindu King of Siam helped spread the word as he visited European capitals as part of his trade mission.
In September and October of 1609, Galileo finally trained his then three-power instrument on the moon, whose rugged surface became visible. He may not have been the first to discover that the moon like the Earth was pockmarked with hills and craters. But in short order, as he continued to perfect his telescope, Galileo discovered the satellites of Jupiter, the rings of Saturn, the phases of Venus, sun spots, and the true cause of the Milky Way. What more did a convinced Copernican need to support a heliocentric view of the universe? In 1610 he published Sidereus nuncius. Six days after it appeared in print, the initial run of 550 copies was sold out.
Instead of universal praise, Galileo met significant opposition. While Kepler, Paolo Sarpi, and Federico Cardinal Borromeo of Milan supported him, and even Paul V for a time, the Pope eventually withdrew his support because of the uncomfortable conclusions to which it led. The Ptolemaic/Aristotelian view of the world order was not easy to abandon. Not only was the authority of Aristotle and the scholastic tradition called into question, but the Bible itself had to be reinterpreted.
And there were political considerations too. Galileo had worked closely with the Venetian prelate, Friar Paolo Sari, a scientist and canon lawyer, who had made important discoveries on his own and who had supported Galileo in his work. When Galileo had failed to acknowledge the support of the Venetian Republic in the Sidereus nuncius and then took up residence in Padua as chief mathematician to the Grand Duke of Tuscany, and professor for life at the university, it had the impact of the victory of one state over another, and lasting enmity on the part of some in Venice.
For Galileo everything would have gone smoothly if he had advanced heliocentrism as purely a mathematical theory, a hypothetical explanation of observed data, yet one not proved. Tycho Brahe knew that Galileo had not demonstrated his conclusion. So too did Cardinal Bellarmine, a convinced Aristotelian who knew the difference between a hypothetical explanation and proof. On April 12, 1615, Bellarmine wrote to Paolo Antonio Foscarini, who had published a troubling pamphlet on Copernican theology. We have the text:
“Very Rev. Father, first I would like to say that you and Mr. Galileo are wise to speak ex suppositione and not in absolute terms, as I always believed Copernicus did. Because so saying, supposing that the Earth moves and the Sun stands still saves all the appearances better than by positing eccentrics and epicycles.”
The proof that Brahe sought but that eluded him was not forthcoming until Friedrich Bessel, director of the Konigsberg Observatory in Prussia, in 1838 was able to measure the parallax of the stars.
Galileo was so convinced that he was right, that he could not leave his conclusion as mere ex suppositione. In 1632 he published his Dialogue Concerning the Two Chief World Systems, in which he in effect defended his view as substantiated. That quickly brought charges of heresy from two old adversaries in Venice. The story of Galileo’s telescope ends here.
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(Dr. Dougherty is dean emeritus of The School of Philosophy, The Catholic University of America.)
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