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Reenacting Galileo's Experiments: Rediscovering the Techniques of Seventeenth-Century Science

Paolo Palmieri
Edwin Mellen Press
Publication Date: 
Number of Pages: 
[Reviewed by
John Perry
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This text is an erudite, carefully prepared immersion into the intellectual world in which Galileo proposed Two New Sciences; it would be of primary interest to specialists in the history of science and philosophy. Problems of special interest include the sinking or rising of an object immersed in water, and whether two simple pendulums swinging through different arcs are isochronous.

The first chapter drops the reader into the middle of a question that will surprise most readers: Did Galileo carry out certain experiments in real life, or did he merely engage in thought experiments? The reviewer remembers suspending a weight from a string in some science class and testing whether the pendulum spans different arclenghts in the same period of time, and he is quite sure that someone told him that this was a reenactment of Galileo’s own work. To the contrary, Dr. Palmieri informs the reader of several scholars’ pronouncements that Galileo did not, in fact, conduct any such experiment. One cited author goes so far as to profess “embarassment” that Galileo performed no such experiment. Palmieri observes that “[this] embarassment… might have been avoided if [he] had repeated Galileo’s experiments; for, he would have seen that there is nothing impossible in what Galileo has to say….” So the title and the first chapter set us up for something quite exciting.

Chapters two and three slow us down a bit to provide philosophical and scientific context. Most natural philosophers of Galileo’s time attempted to explain physical phenomena from Aristotelian premises. Palmieri pays particular attention to Girolamo Borri and Giacomo Zabarella, two contemporaries of Galileo. Palmieri describes in detail their difficulties in attempting to explain motion, even to reconcile it with lived experience. Palmieri refers to this as the “puzzle-box,” and when he turns to Galileo’s reasoning, he explains how the latter breaks free of the puzzle-box by borrowing from and expanding on Archimedean principles. Galileo’s reasoning and principles developed over time, and the author notes that Galileo never gave any summary of his experimental methods; given that, there is certainly a need to reconstruct Galileo’s thinking. This section is heavy in Aristotelian terminology; Palmieri provides some explanation, but the reader unfamiliar with the vocabulary of “accidental” and “essential”, “potential” and “actual” will find it hard going.

Despite the title, the main body of the book contains no discussion of any reenactments of Galileo’s experiments. For whatever reason, we come to these reenactments in the appendices. Of interest are Appendix 1, on certain computer models, and Appendix 2, on a physical reenactment of the pendulum experiment. Palmieri recorded his reenactments, and the text directs the reader to a website that contains nearly fifty videos. The videos are interesting and effective. The reviewer was disappointed to find that the videos lack any sound; this may have been a technical glitch with his computer setup, but if not, some audio commentary would have been useful. In any case, the appendices provide a narrative, directing the reader to the relevant videos.

John Perry is an assistant professor of mathematics at the University of Southern Mississippi. His mathematical interests lie primarily in computational algebra. He once had a number interests outside of mathematics, but after three children and several home renovations he has forgotten what it means to have free time.

1. Galileo and Experiment
2. The Puzzle-Box
3. New Science
Appendix 1. The computer models
Appendix 2. The repetition of Galileo’s pendulum experiments
Appendix 3. Galileo’s pendulum texts
Name and Subject Index