- A great French philosopher and mathematician. One
of Descartes's theories attempted to explain the workings of the
solar system by suggesting that space was filled with infinite,
miniscule, invisible particles, whose motion created vortices that
whirled the planets around the sun. The theory enjoyed popularity
in the 17th century but was eventually displaced by Newton's theory
of universal gravitation.
- An astronomer in the Royal Society, and the namesake
of Halley's Comet. Halley was a close friend of Newton, and assisted
in the publication of the Principia
- A prominent scientist in the Royal Society, of which
he was first secretary, and then president. Hooke became a rival
of Newton in the 1670s, when the two men quarreled over their respective
theories of light. He later felt that Newton had stolen from him
the idea for the mathematics of gravity, and when Newton won fame
after the publication of the Principia
, Hooke grew
bitter and deeply resentful.
Gottfried von Leibniz
- A brilliant German mathematician, and a contemporary
of Newton. The two men developed a bitter feud in the early 1700s
over who had first invented calculus.
- Newton's mother. His father died before he was born,
and when Isaac was only three Hannah remarried and moved away,
leaving the boy to be raised by an uncle. This abandonment must
have been traumatic for the young Isaac; many biographers have
speculated about its impact on his later psychological make-up--
specifically his fierce insecurity.