Galileo never took an IQ test. The ≈185 is Catharine Cox's 1926 estimate after correcting for adult achievement; her figure from his childhood records alone was substantially lower.
A musician's son who timed a swinging lamp
Born in Pisa in 1564, the son of the lutenist and music theorist Vincenzo Galilei, Galileo was sent to study medicine and drifted to mathematics. The story that he timed a swinging cathedral lamp against his pulse comes from his first biographer, and may be embellished.
As a professor at Pisa and then for eighteen years at Padua, he studied falling bodies, pendulums and projectiles — work that cut against Aristotle and led directly to Newton's mechanics.
Education, rolled down an inclined plane
He found a ball rolling down a slope covers distances in the ratio 1, 3, 5, 7… Each stage below is offset by that same rule — his law of falling bodies, applied to his own schooling.
Schooled by Camaldolese monks near Florence and briefly became a novice, until his father brought him home.
Enrolled to study medicine, his father's choice for a well-paid career.
Overheard the Tuscan court mathematician teaching Euclid, and began private lessons in geometry and Archimedes.
Money ran out; he left without graduating and tutored mathematics in Florence and Siena.
Two lectures on the geometry of Dante's Inferno — its shape, size and location — that helped win him a reputation.
Appointed at 25 with the backing of the mathematician Guidobaldo del Monte.
Watch the “Medicean stars” move
Four bodies circling another planet broke the idea that everything orbits the Earth. With the phases of Venus, mountains on the Moon and sunspots, his telescope turned Copernicus's model from a calculation into something you could see. He named the moons after the Medici — and got a court post in Florence for it.
His Dialogue Concerning the Two Chief World Systems (1632) argued for a Sun-centred cosmos and put the Pope's own argument in the mouth of a character called Simplicio. Tried the next year, he was forced to recant and sentenced to house arrest, which he served at Arcetri near Florence until his death in 1642.
He kept working under arrest, dictating to pupils after he went blind. The Church formally acknowledged its error in 1992.
The complete works, instrument by instrument
Books, treatises and the devices he built to test them, in order.
A hydrostatic balance for measuring density, inspired by Archimedes.
Early work on motion, criticising Aristotle; unpublished in his lifetime.
On simple machines — levers, pulleys, screws.
A calculating instrument he sold with a printed manual in 1606.
Ground his own lenses, raising magnification from about 3× to about 20×.
Argued that objects float by density, not by shape.
Showed sunspots lie on the Sun's surface and that the Sun rotates.
Argued that scripture teaches how to go to heaven, not how the heavens go.
A polemic on comets and scientific method, dedicated to the new pope Urban VIII.
The book that led to the trial above.
Smuggled out and printed in Leiden: the foundations of mechanics and the strength of materials.
“Eppur si muove.”
“Philosophy is written in this grand book, the universe… It is written in the language of mathematics.”
Timeline
Reading the ≈185
Cox's adult-corrected estimate; her childhood-records figure was much lower. A retrospective inference from biography, not a measurement.
Sources
- Cox, C. M. (1926). The Early Mental Traits of Three Hundred Geniuses
- Galilei, G. (1610). Sidereus Nuncius
- Galilei, G. (1632). Dialogo sopra i due massimi sistemi del mondo
- Galilei, G. (1638). Discorsi e dimostrazioni matematiche intorno a due nuove scienze
- Heilbron, J. L. (2010). Galileo. Oxford