Lawrence Today magazine, Spring 2003
To be published in the forthcoming issue of Archive for History of Exact Sciences: Bruce Brackenridge, “Newton’s Easy Quadratures ‘Omitted for the Sake of Brevity’” and Bruce Pourciau, “Newton’s Argument for Proposition 1 of the Principia.”
A quiz: What do these two articles have in common? Perhaps the most obvious similarity is that they are both concerned with Sir Isaac Newton’s great work: The Mathematical Principles of Natural Philosophy, commonly called the Principia — a book more revered than read.
Second, both authors are on the Lawrence University faculty: the first is a professor emeritus of physics, and the second is a professor of mathematics.
To complete the comparison, both have the same given name. To avoid confusion, they have taken to referring to each other as Bruce the Younger and Bruce the Elder (with apologies to the Roman Plinys).
What follows is the tale of the role Lawrence University has played in leading a physicist and a mathematician down the trail of historical research.
Bruce the Elder (né Brackenridge) joined the faculty in the fall of 1959. He brought with him a grant from the Research Corporation that was renewed in 1960, and he spent his first sabbatical, in 1965, at Brown University doing experimental physics.
But other forces were at work. His wife, Mary Ann Rossi, a classical scholar with interests in Greek and Roman archaeology, introduced him to the excavations of Heinrich Schliemann in Greece and of Arthur Evans in Crete. In the summer of 1962, they attended a scientific conference in Denmark and extended their trip in order to visit classical sites in Italy. In the Roman Forum, he bent down and placed his fingers in the ruts cut into the stone by the wheels of the ancient chariots. Like Saul on the road to Damascus, he arose a changed man. Suddenly history came to life.
Returning to Lawrence, he was asked (selected, cajoled, ordered) to participate in the Freshman Studies program, where the first work to be read was Plato’s Republic. Now the intellectual world of antiquity, as well as the physical, was opened for him. In 1967 he was chair of the book-selection committee for Freshman Studies when Professor of Government Chung-Do Hah suggested a recent book that might be of interest, Thomas Kuhn’s The Structure of Scientific Revolutions. Over the next two years, he served as director of Freshman Studies, and in 1995 he published an article entitled “Kuhn, Paradigms, and Astronomy: Astronomy as a Case Study of Kuhnian Paradigms.”
The final push came in 1970 in an upper-division physics class from a student who asked quite innocently, “How did Newton ever think of that?” Bruce the Elder realized that he had never even seen a copy of Principia, much less read it, although that did not deter him (à la Kuhn) from repeating what the textbooks said that Newton had said.
In 1973 he spent his second sabbatical as an academic visitor in the history of science department at Imperial College, University of London. The following year he remained in London as director of the Lawrence London Centre, and while there he offered a tutorial in Newton’s Principia to two junior physics majors (innocents abroad). The course was an awakening experience for all three of them.
In 1976, Bruce the Younger (né Pourciau) joined the Lawrence mathematics faculty. His teaching was, and still is, concentrated on contemporary mathematics, and his scholarly research was centered on current topics in that field.
He first taught Freshman Studies in 1979 and later served as director. Reading Plato and Kuhn rekindled his interest in the foundations of mathematics and science and ultimately led to two papers on the philosophy of mathematics: “The Education of a Pure Mathematician” and “Intuitionism as a (Failed) Kuhnian Revolution in Mathematics.” In 1990 Bruce the Younger’s scholarly interests remained mathematical and philosophical but not historical. In particular, Newton’s Principia was for him a closed book, as it had been for Bruce the Elder 20 years earlier. This situation was about to change, for once again, other forces were at work.
In 1982, Bruce the Elder published his first paper in the history of science. It was not on Newton, however, but on Johannes Kepler, the German astronomer who, in 1609, published the great heliocentric work on the motion of Mars: the Astronomia Nova. The first proposition in Principia is the mathematical demonstration of Kepler’s area law, and it is on that first proposition that much of what follows depends.
That same year, a mathematician turned physicist at Oberlin College published a paper titled “Dismantling a Centuries-old Myth: Newton’s Principia and Inverse-square Orbits,” in which he accused Newton of knowingly papering over logical flaws in his proof of elliptical orbits and stated, moreover, that historians of science had either failed to appreciate Newton’s crime or, even worse, joined in the cover up.
Bruce the Elder became embroiled in a continuing correspondence with the author and soon began to look around for a mathematician to help him in the struggle. Enter Bruce the Younger, who took up the cudgels and in the best Brer Rabbit tradition got Bruce the Elder off the hook.
In 1991, Bruce the Younger published a paper arguing that careful examination of the logical structure of Newton’s outline does reveal a flaw, but one that is a minor omission and easily repaired. The argument on that topic continued, and now Bruce the Younger was hooked on the subject.
Over the next decade he followed this initial paper with a series of excellent publications on various mathematical aspects of the Principia. His penultimate paper is the one referred to in the introduction to this article.
In 1990, the same year as Bruce the Younger’s first contact with the Principia, Bruce the Elder received a grant of $92,000 from the National Endowment for the Humanities to prepare a guided study to the Principia with a partial translation from the first (1687) Latin edition. (Remember that his wife is a classical Latin scholar who helped get him into this situation.) The project culminated in the publication of his book, The Key to Newton’s Dynamics, by the University of California Press in 1995. The book also spun off a number of journal articles, including the one now being published in the same journal as Bruce the Younger’s article.
What, then, is the moral to be drawn from this tale of academic seduction? Perhaps it is this: When Lawrence President Nathan Pusey introduced Freshman Studies into the curriculum in 1945, as much to educate the faculty as the students (as he admitted later), he knew exactly what he was doing.
J. Bruce Brackenridge, professor emeritus of physics, passed away on May 3, 2003, shortly after publication of this article. In remembrance.
Professor Brackenridge's Publications
Professor Pourciau's Publications
