The Reception of the Galilean Science of Motion in Seventeenth-Century Europe.
Shank, Michael H.
Carla Rita Palmerino and J. M. M. H. Thijssen, eds., The Reception
of the Galilean Science of Motion in Seventeenth-Century Europe.
Boston Studies in the Philosophy of Science, vol. 239. Dordrecht,
and Boston: Kluwer Academic Publishers, 2004. 275 pp. index. illus.
bibl. $109. ISBN: 1-4020-2454-1.
Nowadays, Galileo's theory of motion is so well received that
we unthinkingly ascribe a positive connotation to this book's
title. Unqualified, however, reception is an ambiguous term: was it
warm? delayed? smooth? hostile? Lacking our easy post-Newtonian
enthusiasm, knowledgeable seventeenth-century readers of Galileo's
Dialogue (1632) and Two New Sciences (1638) saw in his theory of motion
multiple conceptual, mathematical, and philosophical problems.
At one end of the reception spectrum, Rene Descartes was a cursory
reader of Galileo who doubted the empirical validity of the
odd-numbers-law of free fall. Sometimes Galileo himself had downplayed
empirical tests before mathematical argumentation. Even judged as pure
mathematics, however, Galileo's science of motion was egregious,
suspiciously treating a falling body's total speed as the sum of a
number of degrees of speed. At the other end, Pierre Gassendi--who did
drop weights from the mast of a moving ship and took the odd-numbers law
as valid--was one of many who wondered at Galileo's silence about
the cause of free fall. In short, Galileo did not always make it easy
for his readers, whose furrowed brows this book explains in rich detail.
I highly recommend Carla Rita Palmerino's lucid introduction
to the collection, since I cannot adequately summarize here, let alone
evaluate, eleven sophisticated, high-quality analytical studies that
mostly address a specialist audience. The synthetic exception is Floris
Cohen's essay. He presents the Scientific Revolution as
Galileo's and Kepler's bridging of the bimillennial
"chasm" (95) between two approaches to nature and their
progeny: the Athenian (natural philosophical) and the Alexandrian
(mathematical). While Cohen's story helps him understand
Descartes's reticence toward Galileo, it sells short the millennial
promiscuity of natural philosophy and mathematics in medieval Arabic and
Latin optics, astronomy, and astrology, to say nothing of the science of
motion.
Alan Gabbey scrutinizes the expression mechanical philosophy,
arguing that these Cartesian words do not refer to a philosophical
program before the 1660s. Sophie Roux, who disagrees, illuminates
fundamental tensions in Descartes's mechanics, especially its
hermetic theoretical seal between speed and heaviness. William Shea shows how Descartes's rejection of the void ca. 1630 surprisingly
led him to see both free fall as "mathematically intractable"
and Galileo's solution as extreme in identifying the physical and
the mathematical.
Two contributions seek to make the invisible visible. Jochen
Buttner, Peter Damerow, and Jurgen Renn argue from Galileo's
unpublished works that the rocky reception of Galileo's work
proceeded from his contemporaries' protection of a "shared
knowledge" (100) that also surfaces in Galileo's manuscripts.
For his part, Enrico Giusti lets Galileo's disciples fill in the
undocumented steps of Galileo's evolution and argues that Galileo
had two theories of free fall.
Palmerino's study of Pierre Gassendi's correspondence
challenges his proto-Newtonian image: his principle of inertia still had
circular elements, and his notion of force did not yield a uniform
continuous acceleration even as he sought the cause behind
Galileo's odd-numbers law of free fall. Cees Leijenhorst
demonstrates that Thomas Hobbes's efforts and struggles paralleled
those of Gassendi: frustratingly, the impacts of bodies could not
produce a uniform continuous acceleration, which Hobbes too sought to
explain by both "attractive" and "impelling forces."
Wallace Hooper's useful survey of sixteenth- and
seventeenth-century tidal theories from Copernicus to Wallis finds in
modern science a partial (but anachronistic) vindication of
Galileo's maligned tidal theory, notably his attention to the shape
of sea basins in explaining tidal periods.
Christiane Vilain sees Christiaan Huygens, who generalized
Galileo's relativity of motion with his own imaginary boat
experiment, as offering a non-inductive, more sophisticated
geometrically-oriented mechanics. Despite debts to both Galileo and
Descartes, Huygens, unlike them, blurred the distinctions between
"natural phenomena, geometrical curves, and machines." Michel
Blay brings Pierre Varignon out of Newton's shadow ca. 1700 and
makes a strong case for the mathematical and physical interest of his
work, notably in his treatments of velocity (as a quotient, at an
instant) and of central forces in relation to rectilinear and curved
trajectories.
As this rich, well-edited collection of first-rate work on the
bumpy reception of Galileo's work shows, the study of early modern
mechanics is thriving in Europe.
MICHAEL H. SHANK
University of Wisconsin-Madison