Galileo Galilei

Early Modern

Born 1564 CE, Pisa

Died 1642 CE

He turned a telescope on the heavens and a mathematician's eye on motion, and was made to kneel for saying the earth moves.

Galileo did more than anyone to make nature speak the language of mathematics. He found that falling bodies obey simple laws, built a telescope and saw mountains on the moon, moons around Jupiter, and the phases of Venus, evidence that the heavens were neither perfect nor turning around us. The book of nature, he wrote, is written in the characters of geometry. His defense of Copernicus brought him before the Inquisition, which forced him to recant and condemned him to house arrest for his last years. The method he modeled (measure, idealize, test) became the engine of modern science.

Galileo turns telescope on Jupiter's moons, book of nature written in geometry, Inquisition shadow over Florence. — Nature speaks in mathematics.

Places

Ideas

Nature Reason

Words

“The book of the universe is written in the language of mathematics, and its characters are triangles, circles, and other geometric figures.”
— Galileo GalileiShare

Works

Dialogue Concerning the Two Chief World Systems

1632 CE·Italian

Galileo's great defense of the Copernican system, staged as a three-day conversation between defenders of the old and new astronomy. Its persuasive force brought him before the Inquisition. His deeper conviction, stated in The Assayer, was that nature speaks the language of mathematics.

Life & Moments

1564 CE

Born in Pisa

Born in the Tuscan city of Pisa, he turned early from medicine to mathematics and motion.

1610 CE

The Starry Messenger

Turned a telescope on the heavens and found mountains on the moon and four moons circling Jupiter, evidence the heavens were not perfect.

1632 CE

Dialogue Concerning the Two Chief World Systems

Published his defense of Copernicus in dialogue form, arguing that the book of nature is written in the language of mathematics.

1633 CE

Before the Inquisition

Tried for defending Copernicus, forced to recant that the earth moves, and condemned to house arrest for his last years.

Influence

Influenced by

Aristotlephysics overturned
Galileo's inclined planes and falling bodies were aimed at the Aristotelian account of motion that the universities still taught, and the Dialogue is organized as a running argument against it.

Influenced

Thomas Hobbesinfluence
Hobbes visited the aging Galileo and modeled his philosophy of bodies in motion on the new mechanical physics.
Descartesa condemnation that silenced a book
Descartes had a treatise on the world ready when he learned of Galileo's condemnation in 1633, and withheld it. What he published afterward was shaped by the knowledge of what the Church would tolerate.