Quick answer“It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it.” is a famous quote by Galileo Galilei. It comes from The Assayer (Il Saggiatore, 1623). It is widely quoted on wisdom and science.
In The Assayer of 1623, Galileo Galilei wrote that philosophy — what we would call natural science — is written in the language of mathematics. The passage is one of the most famous statements ever made about how science works.
Origin: From Galileo's Il Saggiatore (The Assayer), published in Rome in 1623, in the translation by Stillman Drake. The full passage runs: 'Philosophy is written in this grand book, the universe, which stands continually open to our gaze. But it cannot be understood unless one first learns to comprehend the language and recognize the letters in which it is composed. It is written in the language of mathematics...' The short form often quoted, 'The book of nature is written in the language of mathematics', is a compression of this passage, not Galileo's own sentence, so the record uses the verified sentence from Drake's translation.
Translated from Italian.
Key facts
| Quote | “It is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures, without which it is humanly impossible to understand a single word of it.” |
|---|---|
| Author | Galileo Galilei |
| Source | The Assayer (Il Saggiatore, 1623) |
| Themes | wisdom, science |
| Language | Italian (translation) |
| Original | “Egli è scritto in lingua matematica, e i caratteri son triangoli, cerchi, ed altre figure Geometriche, senza i quali mezzi è impossibile intenderne umanamente parola.” |
Overview
Galileo was answering an attack on his ideas about comets, and he used the image of the universe as a great book, open before our eyes. The book cannot be read, he argued, unless you first learn its language, and that language is mathematics: its characters are triangles, circles and other geometrical figures. Without them, he wrote, 'one is wandering about in a dark labyrinth'. The passage matters because it states a new idea plainly: nature is not understood by quoting authorities, but by measuring and calculating. The short form people quote — 'The book of nature is written in the language of mathematics' — compresses Galileo's sentence; his own words begin 'Philosophy is written in this grand book, the universe'. The Italian original, Il Saggiatore, was published in Rome in 1623.
Frequently asked questions
What is The Assayer?
Il Saggiatore (The Assayer) is a book Galileo published in Rome in 1623, answering a Jesuit critic who had attacked his views on comets. It defends the use of mathematics and experiment in studying nature, and it contains the famous passage about the book of the universe.
Did Galileo write 'the book of nature'?
Not in those words. The popular short form compresses his sentence. Galileo wrote that philosophy is written in 'this grand book, the universe', and that 'it is written in the language of mathematics'. The idea is his; the neat short sentence is a later summary of it.
What did Galileo mean?
He meant that nature cannot be understood by argument from books and authorities alone. To read the universe you must learn mathematics, because its patterns are geometrical: triangles, circles and other figures. Without that language, he said, you wander in a dark labyrinth.
Was the book written in Italian?
Yes. Il Saggiatore was written in Italian, not Latin, so that educated readers outside the universities could follow it. The English wording on this page follows Stillman Drake's translation, the standard English version used by historians of science. Galileo chose Italian deliberately, as a statement that natural philosophy belonged to a wider public.
Related quotes
- “All the world's a stage, and all the men and women merely players.” — William Shakespeare
- “An expert is a person who has found out by his own painful experience all the mistakes that one can make in a very narrow field.” — Niels Bohr
- “I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.” — Isaac Newton
- “Brevity is the soul of wit.” — William Shakespeare
- “Give me a place to stand, and I shall move the Earth.” — Archimedes
Quick quiz
Three questions from the facts on this page. No sign-up, no score is saved.
Keep exploring
- All quotes — the full list
- More quotes on wisdom
- More quotes on science
- Galileo Galilei — the author's life and facts
Sources & last updated
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.