Senses, Reason and the Heavens: Galileo's Letter to a Grand Duchess

Patrons, Presses and the Heavens

1The Renaissance, a “rebirth” of interest in the learning and art of ancient Greece and Rome, began in the city-states of Italy in the 1300s and 1400s. Painters such as Leonardo da Vinci studied light, shadow and the human body so closely that their pictures looked real. In Florence, rich families such as the Medici acted as patrons, paying artists and scholars to work for them. The young Michelangelo lived for a time in the household of Lorenzo de' Medici, and Botticelli painted for Medici patrons. A patron brought money and fame, but artists also had to please the people who paid them.

2Printing spread new work quickly. After Johannes Gutenberg built a press with movable metal type in Mainz in about 1450, presses appeared across Europe, and scholars in many cities could read the same text. In 1543 a printed book by Nicolaus Copernicus argued that Earth and the planets move around the Sun. Most scholars still followed the ancient view that Earth stood still at the center of the universe.

3In 1609 Galileo Galilei, a professor at the University of Padua, built telescopes and turned them to the sky. He saw mountains on the Moon, many stars too faint for the eye and four moons circling Jupiter. In 1610 he named the moons the “Medicean Stars” in honor of Cosimo II de' Medici, the young Grand Duke of Tuscany. Months later Cosimo made him his court mathematician and philosopher, and Galileo moved to Florence. Late that year he saw that Venus shows phases like the Moon.

4Some professors and preachers objected that a moving Earth went against passages in the Bible, such as one that says the sun stood still. In December 1613, at a breakfast at the Medici court in Pisa, Cosimo's mother, the Grand Duchess Christina, asked Galileo's former student Benedetto Castelli how the new ideas fit with the Bible. Galileo answered in a letter to Castelli, and in 1615 he expanded it into a long letter addressed to Christina herself.

5The debate grew. In 1616 the Church declared the idea that Earth moves around the Sun contrary to the Bible, banned Copernicus's book until it was corrected and told Galileo not to hold or defend the idea. In 1632 Galileo published a Dialogue comparing the two views, written in Italian rather than Latin so that more readers could follow it. In 1633 a Church court found him guilty, made him take back his view and kept him under house arrest until his death in 1642.

Adapted from an English translation of Galileo's Letter to the Grand Duchess Christina (1615)

1Some years ago, as Your Highness well knows, I discovered in the heavens many things that had not been seen before our own age. Because they were new, and because of some ideas that follow from them, a number of professors were stirred up against me, as if I had placed these things in the sky with my own hands to upset nature and overturn the sciences.

2These men have tried to spread the opinion that my ideas go against the Bible. I believe that in questions about nature we ought to begin not from the authority of Bible passages, but from what our senses show us and from careful proofs.

3I do not feel obliged to believe that the same God who gave us senses, reason and intellect wants us to give up using them. As a churchman of high rank once said, the Bible's purpose is to teach us how one goes to heaven, not how the heavens go.