Galileo Galilei (1564-1642): Science and Religion – Part Ia: Why the Jews?

The Renaissance, the Protestant and Catholic Reformations, the Scientific Revolution and the communication revolution as a result of the invention of moveable type, that all began or took place in the sixteenth century, altered the view of the world and impacted the lives of both Jews and Christians in Europe in the seventeenth century. In the spring, I gave a series of lectures on some greats in the sixteenth century transitional period between the medieval and the modern period and the relationship between these important figures and Jews and Judaism. How did the many different dimensions of those interactions play out in the seventeenth century?

As autumn comes to an end, I plan to give three more lectures (and write corresponding blogs) on great figures of the seventeenth century and their relationship to Jews. They include Galileo Galilei, Francis Bacon, Hugo Grotius, Blaise Pascal, Thomas Hobbes and John Locke. Lurking in the background throughout this survey will be Baruch Spinoza, a Jew ex-communicated from his congregation in Amsterdam in the seventeenth century.  

I begin with Galileo Galilei. Why Galileo?

Personal Identification

It could be personal. Galileo’s daughter, a cloistered nun in San Matteo, on 18 October 1630, when her father was on the verge of publishing his most famous book, Dialogue Concerning the Two Chief Systems of the World, wrote her father a letter. In her pattern of self-renunciation and humility, combined with her enormous respect and love for her father, she asked rhetorically, “If you could teach me the secret you yourself employ, Sire, for getting by on so little sleep, I would be most grateful.” (Sobel 199) I identify with Galileo. He slept little. So do I.

Further, like myself he went to medical school for two years before he shifted to mathematics and physics; I went on to study philosophy after two years of medical school. Perhaps my choice of Galileo was because I identified with him, not only for the few hours of sleep he enjoyed each night, but because I have always been overwhelmed by his scientific achievements. In addition, I identified with him because he disdained academic dress and manners. When I first taught at Trinity College at the University of Toronto, I was required to wear an academic gown. I did as I was required, but I used my gown to erase the chalk marks I made on the blackboard. Galileo also “deemed official doctoral dress a pretentious nuisance.” (Sobel 19)

Finally, it could be because some of his enemies spread rumours that Galileo was a Jew, a man from the Galil. The rumour was patently false and had no merit whatsoever, but we are well acquainted with “fake news” these days and false allegations that it was the Ukrainians, not the Russians, who interfered in the American 2016 elections.

Galileo’s Interactions with Jews

Galileo had some interaction with Jews. However, those contacts were infrequent and exceptional. For example, he did write a letter to the 17th century Jewish mathematician, astronomer, astrologer and physician, Jacob Rosales of Hamburg, one of the three Hanseatic cities. (The others were Danzig and Lűbeck.) Galileo had presumably met Rosales when the latter lived in Rome. They had much in common, but also a number of fundamental differences, both on science and religion. Rosales, for example,nseatic cities that included Danzig and Lbeck as well,Hanseatic cities also happened to be a Sebastianist, an exponent of political messianism.

A bit more on Rosales. Christened Imanuel Bocarro Francês in 1593 in Lisbon, Rosales became an ex-Marrano who returned to Judaism after his escape to Hamburg (1631-1652). Subsequently, he was denounced by the spy on the Sephardic Jewish community throughout Europe, Semuel Aboab, alias Francisco Domingo de Guzmán, but this informer to the inquisition operated between 1661-2, well after Galileo’s death. When Galileo was in touch with Rosales, it was over a dispute between modern science and Rosales’ commitment to traditional science and astrology. Galileo admired Rosales for his proficiency in astrology, but was never persuaded of its scientific bona fides.

Galileo himself dabbled in astrology. Any physician trained in Europe at the time had to be an accomplished astrologer, since doctors were then required to cast horoscopes in order to see what the stars adumbrated of the patient’s life. Astrology was intended to assist in diagnosis, in prescribing remedies and even in understanding the causes of specific diseases. However, Galileo never took astrology seriously. He engaged in it at the request of a patron, such as that of Madama Christina when Grand Duke Ferdinando was ill, but he joked that astrologers really only saw things in retrospect.

A plethora of Jewish physicians lived in Hamburg and Amsterdam in the seventeenth century, many of them mentored by the very illustrious Rodrigo de Castro, another Marrano who reverted back to Judaism. In de Castro’s theory of plagues, those epidemics were the result of the spread of extremely small organisms, a theory clearly in advance of his time and the germ theory of disease established two centuries later when it was determined that the plague resulted from microbes living in and on rats; the fleas living on those rats spread the disease when a rat died and the fleas migrated to another host.

At the time, although the accumulation of dead rats adumbrated the arrival once again of the plague – never as horrific as the fourteenth century when one-third of the population of Europe died – the widespread belief was that the disease resulted from “swamp air,” or, more often, a full moon in conjunction with specific positions of the planets. Famine supposedly played a part. But it was the stellar conjunctions that were used to trace the course of the disease and its treatment.

That was the supposedly scientific side. On the irrational populist side, beggars and Jews were accused of being responsible for the spread of the plague. Further, Galileo’s daughter pronounced to her father that the plague resulted from insufficient prayer and piety. Galileo himself, though he had observed microbes through his telescope, never recognized even de Castro’s and Rosales’ early version of germ theory.

Rosales was more enamoured with astrology as a guide to medical practice than any subscription to a proto-germ theory. In fact, as Isaac Cordoso wrote on the death of Rosales’ only son at 17 years of age, “when his only son fell sick, the stars told him he would be healthy and enjoy long life. But his son died at the age of 17, because his father trusted more in the stars than in the mortal signs of danger and in [the healing power of] medicines.” Christian physicians in Hamburg, though also proficient in astrology, were more inclined to rely on bleeding and medicines than astrology.

Galileo’s contact with Rosales predated his move to Hamburg. Rosales had fled first fled from Lisbon to Rome after he had been denounced as a heretic. He lived there until at least 1629 and possibly until 1632 when Galileo’s most famous book was published. In Rome, Rosales published the fourth part of his banned book, Anacefaleoses (the contemporary meaning is related to the congenital absence of part of the brain) and his separately published notes in his volume Luz Pequena Lunar.

Rosales’ book envisioned the heavenly monarch as eternal, divine and perfect; it was related to the sun, equally perfect according to Aristotelian and Ptolemaic cosmology. Earthly monarchies, in contrast, were imperfect, lacked in effect part of a brain, particularly the Portugese monarchy. Earthly monarchies were linked with lunar light and linked with its deficiencies. What would Rosales have thought of the moon, and, by extension, earthly monarchies, if he had learned that the moon had no light of its own but merely reflected the light of the sun?

Rosales was also renowned for his poetry “in Spanish, Portuguese and Neo-Latin to expound his theories about the human and divine knowledge.” He also wrote encomia in praise of his friends and colleagues. Unequivocally, he had great admiration for Galileo as a mathematician, a scientist and an astrologer, but seemed unaware of Galileo’s scepticism of the latter subject.

What comes across is Galileo’s total indifference to whether Rosales was a Christian, a Marrano or a believing Jew which he became. Mathematics and science were the new universal language. In contrast, in spite of the apparent greater tolerance for Jews in Hamburg, Christian physicians were rivals of Jewish physicians because of the so-called Jewish medical practices. But there was also a great jealousy of the Jews from Portugal, for the mercantilist elite of Hamburg engaged in banking and international trade, primarily with Brazil, lived in incredible luxury and in huge mansions.

To be continued.


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