Newton never took an IQ test. Catharine Cox's 1926 study rated him 130 from his thin childhood records and ≈190 after correcting for adult achievement. The 60-point gap measures what was written down about a Lincolnshire farm boy, not his ability.
A thin record for a Lincolnshire boy
Born on Christmas Day 1642 (January 4, 1643, by today's calendar) at Woolsthorpe Manor, three months after his father's death, Newton was left with his grandmother when his mother remarried. He hated his stepfather, and as a teenager wrote a list of his sins that included threatening to burn the house down with his mother and stepfather inside.
He was a solitary, inventive boy who built sundials, a model windmill powered by a mouse and paper lanterns carried on kites that frightened the neighbours at night.
Education, from the college register
From a Grantham grammar school to the Lucasian Chair in eight years. Each entry is headed the way Cambridge recorded it.
Latin, Greek and scripture; lodged with the apothecary William Clark, whose chemicals and books fascinated him. Poor at first, top of the school by the end.
His mother withdrew him to run the estate. He neglected the sheep to read; headmaster Henry Stokes persuaded her to send him back.
Admitted on 5 June as a sizar, paying his way with servant duties.
Began “Certain philosophical questions”, teaching himself Descartes, Galileo, Kepler and Boyle outside the old Aristotelian syllabus.
Elected a scholar, securing his place for four more years.
Graduated without distinction just before plague closed the university.
Elected a fellow of Trinity, then took his MA.
At 26, succeeding his mentor Isaac Barrow, who stepped aside in his favour.
Eighteen months of plague, three revolutions
With Cambridge shut by the Great Plague in 1665–66, Newton went home to Woolsthorpe. The apple story is his own, told late in life — more teaching aid than history.
He sat on most of it for decades. The calculus wasn't fully published until 1736, and Leibniz, who got there independently, published first in 1684 — the start of a long, damaging priority fight.
Halley's question: what orbit does gravity make?
In 1684 Edmond Halley asked what path an inverse-square force produces. Newton said an ellipse — then went looking for his old proof. Halley paid to print the book that followed. Change the launch speed and see every conic section fall out of one law.
The Principia set out the three laws of motion and universal gravitation, derived Kepler's laws, and explained the Moon's orbit and the tides — in dense Latin geometry. It made him famous across Europe: President of the Royal Society from 1703 until his death, and in 1705 the first scientist knighted in this way.
Meant as a comfortable reward post, the Mint became his last obsession. As Warden and then Master he ran the Great Recoinage and personally hunted counterfeiters — then a hanging offence — and helped put Britain on a de facto gold standard.
He wrote more on alchemy and biblical prophecy than on physics — over a million words, mostly unpublished in his lifetime. Keynes, who bought many of the papers, called him "the last of the magicians".
The complete works, by title page
He published reluctantly and late. Several of his most important works appeared only after his death.
On analysis by infinite series — circulated privately, it established his reputation with Barrow and others.
Built the first practical reflector; it won him fellowship of the Royal Society in 1672.
His first published paper, in Philosophical Transactions; the dispute with Hooke it provoked made him wary of publishing.
A short tract for Halley on orbits — the seed of the Principia.
Three editions; the second added the General Scholium with his famous “hypotheses non fingo”.
Published anonymously: his law of cooling.
In English, with the Queries speculating on light, matter and gravity; also included two mathematical tracts.
His lectures on algebra, published from notes.
Posthumous: an attempt to date ancient history using astronomy.
Posthumous: his biblical interpretation.
Written in 1671, published only after his death — his full account of calculus.
"If I have seen further it is by standing on the shoulders of Giants."
Timeline
Reading the ≈190
Cox's childhood-based figure was 130; the 190 is her correction for adult achievement. Both are retrospective inferences from biography, not measurements.
Sources
- Cox, C. M. (1926). The Early Mental Traits of Three Hundred Geniuses
- Newton, I. (1687). Philosophiæ Naturalis Principia Mathematica
- Newton, I. (1704). Opticks
- Westfall, R. S. (1980). Never at Rest. Cambridge
- Keynes, J. M. (1946). "Newton, the Man"