Galileo Galilei · Science
The collision between Galileo’s Copernicanism and the Church - and what the trial really teaches about evidence, authority, and who may decide the truth.
By 1615 Galileo’s public championing of a Sun-centred cosmos had collided with Scripture. Critics pointed to passages where the Bible speaks of a moving Sun and a fixed Earth - most famously Joshua commanding the Sun, not the Earth, to stand still. If the Earth really moves, they said, the holy text is in error, which cannot be. Galileo, a devout Catholic who had no wish to attack the faith, wrote a long, careful open letter to the Grand Duchess Christina to defend how a believer should read such passages.
Galileo’s framework is elegant. God is the author of two books: the book of Scripture and the book of nature. Both are true, because both come from God, so they cannot genuinely contradict each other. But they speak in different languages and serve different ends. Scripture, accommodating itself to ordinary understanding, teaches the way to heaven. Nature, written in mathematics and read by observation and reason, shows how the heavens actually go. Where they seem to clash, we have misread one of them - and on physical matters, he insisted, we should not bend nature’s plain evidence to a strained reading of a sacred text.
The crisis came not from the telescope but from a book. In 1632 Galileo published the Dialogue Concerning the Two Chief World Systems, a brilliant, vivid comparison of the Ptolemaic and Copernican systems that left no honest reader in doubt which side had won. He believed he had permission; the Church believed he had violated the 1616 injunction not to hold or defend Copernicanism. Summoned to Rome in 1633, the sick and ageing Galileo was interrogated by the Inquisition, shown the instruments of the process, and found ‘vehemently suspect of heresy.’ On 22 June 1633, kneeling before the cardinals, he read aloud a formal abjuration, renouncing and cursing the opinion that the Earth moves. He was sentenced to imprisonment, soon commuted to house arrest, under which he would remain until his death in 1642. The legend says that as he rose he muttered ‘Eppur si muove’ - ‘and yet it moves’ - almost certainly a later invention, but a true one in spirit: a man can be forced to say the Earth stands still, and the Earth will go on moving regardless.
This is the opening of the lesson. The rest — the dialogue, the primary source, and the recall — is in the app.
You learned Galileo argued that Scripture and nature cannot truly conflict. Reconstruct his ‘two books’ argument and say what its weak point was, in your own words.
Leads to Benedict de Spinoza.
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