Galileo Tate, Carson, Riley, Dalton

Galileo Galilei (1564–1642) has always played a key role in any history of science and, in many histories of philosophy, he is a, if not the, central figure of the scientific revolution of the 17th century. His work in physics or natural philosophy, astronomy, and the methodology of science still evoke debate after over 360 years. His role in promoting the Copernican theory and his travails and trials with the Roman Church are stories that still require re- telling. This article attempts to provide an overview of these aspects of Galileo's life and work, but does so by focusing in a new way on his discussions of the nature of matter.

Galileo was born on February 15, 1564 in Pisa. By the time he died on January 8, 1642 (but see problems with the date, Machamer 1998, pp. 24–5) he was as famous as any person in Europe. Moreover, when he was born there was no such thing as ‘science’, yet by the time he died science was well on its way to becoming a discipline and its concepts and method a whole philosophical system.

It was during his Paduan period that Galileo worked out much of his mechanics and began his work with the telescope. In 1610 he published The Starry Messenger, and soon after accepted a position as Mathematician and Philosopher to the Grand Duke of Tuscany (and a non-teaching professorship at Pisa). He had worked hard for this position and even named the moons of Jupiter after the Medici. There were many reasons for his move but he says he did not like the wine in the Venice area and he had to teach too many students. Late in 1610, the Collegio Romano in Rome, where Clavius taught, certified the results of Galileo's telescopic observations. In 1611 he became a member of what is perhaps the first scientific society, the Academia dei Lincei.

For most people, in the 17 th Century as well as today, Galileo was and is seen as the ‘hero’ of modern science. Galileo discovered many things: with his telescope, he first saw the moons of Jupiter and the mountains on the Moon; he determined the parabolic path of projectiles and calculated the law of free fall on the basis of experiment. He is known for defending and making popular the Copernican system, using the telescope to examine the heavens, inventing the microscope, dropping stones from towers and masts, playing with pendula and clocks, being the first ‘real’ experimental scientist, advocating the relativity of motion, and creating a mathematical physics. His major claim to fame probably comes from his trial by the Catholic Inquisition and his purported role as heroic rational, modern man in the subsequent history of the ‘warfare’ between science and religion. This is no small set of accomplishments for one 17th Century Italian, who was the son of a court musician and who left the University of Pisa without a degree.