Galilei, Galileo (1564–1642)

The life and works of Galileo Galilei have been recounted numerous times and in a variety of ways in the 400 years since he lived. He has been studied as one of the first modern scientists, as an astronomer, a physicist, and a man of the late Italian Renaissance. Here we will look at him from a more social angle, which has been less explored and is especially relevant in this encyclopedia: the role that public communication plays in the development of science. In Galileo's time, what we now know as science was not at all well defined. Neither the practices nor the people and places were clearly established. This meant that the study of nature could be done in more than one way, and Galileo created his own approach, and he used all the means of communication at hand to promote it.

At the beginning of the 17th century, Galileo was a teacher at the University of Padua, in the north of Italy. He had learned mathematics mostly on his own and obtained this teaching position by a combination of his intellectual abilities and his good connections. This was not unusual in his time. Inside the universities of that time things were very strictly defined: Teachers were to review and at most comment on the classics with their students. Mathematicians were something like technicians who used their knowledge for practical tasks such as designing fortifications or hydraulic systems. Philosophers, on the other hand, were in charge of the theoretical discussions of the essence and structure of things in nature, such as life or the universe. The social structure was such that these two kinds of professionals did not mix.

In the period in which Galileo worked at Padua, when he was not busy teaching, he studied the motion of bodies. For this purpose, he read the works of his predecessors and also thought about and did experiments. He soon found that he did not agree with all of the knowledge inherited from Greece and Rome. He could not say this in the university, of course, but he discussed it with friends, wrote letters to other mathematicians, and taught it to his private students. And because he was a mathematician, he definitely could not discuss it with the philosophers, who were practically the owners of the subject.

Universities of that time were rather constraining, both in the subjects that could be taught and in their social structure. Through his letters we can see that Galileo was constantly looking for a way out, and he had his eye on a position in the court. In 1610, he had a lucky break, for among his first telescopic observations he discovered four little stars gyrating around the planet Jupiter. He dedicated this discovery to the house of the Duke of Medici, whose founding father Cosimo was identified with the figure of Jupiter. As a result, he managed to move both physically and professionally: He went from the university in Padua to the court in Florence and became the “philosopher and mathematician of the Grand Duke.”

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