Critics

Newton could not stand criticism, and he had many critics. The most prominent
and influential of these were Robert Hooke in England, and Christiaan Huygens
and Gottfried Leibniz on the Continent.
Hooke has never been popular with Newton partisans. One of his contemporaries
described him as “the most ill-natured, conceited man in the world, hated
and despised by most of the Royal Society, pretending to have all other inventions
when once discovered by their authors.” There is a grain of truth in this
concerning Hooke’s character, but he deserves better. In science he made contributions
to optics, mechanics, and even geology. His skill as an inventor was
renowned, and he was a surveyor and an architect. In personality, Hooke and
Newton were polar opposites. Hooke was a gregarious extrovert, while Newton,
at least during his most creative years, was a secretive introvert. Hooke did not
hesitate to rush into print any ideas that seemed plausible. Newton shaped his
concepts by thinking about them for years, or even decades. Neither man could
bear to acknowledge any influence from the other. When their interests overlapped,
bitter confrontations were inevitable.
Among seventeenth-century physicists, Huygens was most nearly Newton’s
equal. He made important contributions in mathematics. He invented the pendulum
clock and developed the use of springs as clock regulators. He studied
telescopes and microscopes and introduced improvements in their design. His
studies in mechanics touched on statics, hydrostatics, elastic collisions, projectile
motion, pendulum theory, gravity theory, and an implicit force concept, including
the concept of centrifugal force. He pictured light as a train of wave fronts
transmitted through a medium consisting of elastic particles. In matters relating
to physics, this intellectual menu is strikingly similar to that of Newton. Yet
Huygens’s influence beyond his own century was slight, while Newton’s was
enormous. One of Huygens’s limitations was that he worked alone and had few
disciples. Also, like Newton, he often hesitated to publish, and when the work
finally saw print others had covered the same ground. Most important, however,
was his philosophical bias. He followed Rene´ Descartes in the belief that naturalphenomena must have mechanistic explanations. He rejected Newton’s theory of
universal gravitation, calling it “absurd,” because it was no more than mathematics
and proposed no mechanisms.
Leibniz, the second of Newton’s principal critics on the Continent, is remembered
more as a mathematician than as a physicist. Like that of Huygens,
his physics was limited by a mechanistic philosophy. In mathematics he made
two major contributions, an independent (after Newton’s) invention of calculus,
and an early development of the principles of symbolic logic. One manifestation
of Leibniz’s calculus can be seen today in countless mathematics and physics
textbooks: his notation. The basic operations of calculus are differentiation and
integration, accomplished with derivatives and integrals. The Leibniz symbols
for derivatives (e.g., ) and integrals (e.g., ∫ydx) have been in constant use for
dy
dx
more than three hundred years. Unlike many of his scientific colleagues, Leibniz
never held an academic post. He was everything but an academic, a lawyer,
statesman, diplomat, and professional genealogist, with assignments such as arranging
peace negotiations, tracing royal pedigrees, and mapping legal reforms.
Leibniz and Newton later engaged in a sordid clash over who invented calculus
first.