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Questions to ask Isaac Newton

8 min read

The best questions for Isaac Newton (1643 to 1727) go beyond the apple: ask about the plague years of 1665 and 1666, why he wrote the Principia only after Edmond Halley's visit in 1684, his fights with Robert Hooke and Gottfried Leibniz, hunting counterfeiters at the Royal Mint, and his private work on alchemy and theology. Here are 25 questions in six groups, what his papers say, and answers in his own words.

Why Newton questions are popular in 2027

Isaac Newton died in Kensington on 31 March 1727 (20 March 1726 by the Old Style calendar England still used), so 31 March 2027 marks 300 years. Expect school projects, museum events and Royal Society talks around that date. Our Newton 300 years article covers the anniversary itself; this page is for students who need to interview him.

The short version of his life: born at Woolsthorpe Manor in Lincolnshire on Christmas Day 1642 (Old Style; 4 January 1643 by the modern calendar), three months after his father died. He studied at Trinity College, Cambridge, became Lucasian Professor of Mathematics in 1669, published the Principia in 1687 and the Opticks in 1704, ran the Royal Mint from 1696, was President of the Royal Society from 1703 and was knighted in 1705. He is buried in Westminster Abbey.

How to get good answers from these questions

Newton was secretive, touchy and very precise. Questions that name a document or a person get better answers than “What was it like to be a genius?”. If you are writing his answers yourself for a wax museum or a first person speech, base them on the record notes under each group, and keep the tone formal: he wrote in long, careful sentences and rarely joked.

To test your questions out loud, you can put them to an AI recreation of Isaac Newton on Yuga, by voice or text. It is built from his writings and the historical record, but it is not Newton and it can make mistakes, so cite his letters and books, never the app.

Childhood at Woolsthorpe and school at Grantham

Record: his mother Hannah remarried when he was about three and left him with his grandmother. A list of sins he wrote in 1662 includes threatening to burn his stepfather's house down. Early memoirs by John Conduitt (his niece's husband) and William Stukeley describe the model windmill and sundials he made as a schoolboy at the King's School, Grantham.

  1. What do you remember of your mother leaving you with your grandmother?
  2. Why did your mother try to make you run the family farm, and why did it fail?
  3. What did you build as a boy in Grantham?
  4. Why did you go to Cambridge as a subsizar, paying your way by serving other students?

The plague years, light and the telescope

Record: Cambridge closed because of plague in 1665, and Newton spent most of 1665 to 1667 at Woolsthorpe. Later in life he said these were his most inventive years: the method of fluxions (his calculus), the prism experiments on colour and the first thoughts on gravity. In 1672 he sent the Royal Society his paper on light and colours and was elected a Fellow after they saw his reflecting telescope.

  1. What did you work on when Cambridge closed for the plague?
  2. How did your prism experiment show that white light is a mixture of colours?
  3. Why did you build a telescope with a mirror instead of lenses?
  4. Why did criticism of your 1672 paper make you want to stop publishing?

Writing the Principia

Record: in August 1684 the astronomer Edmond Halley visited Cambridge and asked what path a planet would follow under an inverse square force. Newton said an ellipse and that he had calculated it. The short tract that followed, De motu, grew into the Philosophiae Naturalis Principia Mathematica, published in July 1687 at Halley's expense. Its General Scholium, added in the second edition of 1713, contains his remarks on method and on God.

  1. What did Halley ask you in 1684, and why had you not published the answer already?
  2. How did you show that the same force holds the Moon in orbit and makes things fall?
  3. Why did you write the Principia in geometry rather than in your new calculus?
  4. What do you mean when you say you frame no hypotheses about the cause of gravity?
  5. Is the story of the falling apple true?

On the apple: Stukeley's memoir (written in 1752) reports that Newton told him in 1726 that seeing an apple fall in the garden at Woolsthorpe set him thinking about gravity. Nothing in any early account says it hit his head. See did an apple fall on Newton's head.

Quarrels with Hooke, Flamsteed and Leibniz

Record: Robert Hooke claimed credit for the inverse square idea, and Newton cut references to him from the Principia. He fought with the Astronomer Royal John Flamsteed over star observations he wanted published. Over calculus, a Royal Society committee reported in the Commercium Epistolicum (1712) that he had priority over Leibniz; Newton himself wrote much of that report and an anonymous review of it in 1715. Historians today credit both men with inventing calculus independently.

  1. What did you mean in your 1676 letter to Hooke about standing on the shoulders of giants?
  2. Why did you remove Hooke's name from parts of the Principia?
  3. Was it fair for you to write the Royal Society's report on the calculus dispute?
  4. Why did you publish Flamsteed's star catalogue without his consent?

The Mint, alchemy and faith

Record: Newton became Warden of the Royal Mint in 1696 and Master in 1699. He ran the great recoinage and personally pursued counterfeiters; the forger William Chaloner was hanged in 1699 after Newton gathered evidence against him. His surviving papers include over a million words on alchemy and many more on theology and prophecy. He privately rejected the doctrine of the Trinity, which could have cost him his posts, and in manuscripts now in the National Library of Israel he reckoned that the prophecies of Daniel and Revelation would not be fulfilled before 2060.

  1. Why did a Cambridge professor take a job at the Mint?
  2. How did you catch William Chaloner?
  3. What were you hoping to find in your alchemy experiments?
  4. Why did you keep your views on the Trinity secret?
  5. Why did you calculate a date for the end of the world, and why did you warn against setting dates?
  6. How did you run the Royal Society as its president?
  7. What happened to you in 1693, when you wrote angry letters to Samuel Pepys and John Locke?
  8. What do you want to be remembered for?

Sample answers in Newton's own words

Q: What did you mean about standing on the shoulders of giants?

“If I have seen further it is by standing on ye sholders of Giants.”
Letter to Robert Hooke, dated 5 February 1675 (Old Style), that is 15 February 1676

Historians read the line as partly courtesy and possibly a jab at Hooke, who was short. Keep the old spelling if you quote it.

Q: How did you make your discoveries?

“But if I have done the public any service this way, 'tis due to nothing but industry and a patient thought.”
Letter to Richard Bentley, 10 December 1692, in The Correspondence of Isaac Newton, vol. 3
“I keep the subject constantly before me, and wait 'till the first dawnings open slowly, by little and little, into a full and clear light.”
Reported reply when asked how he made his discoveries, quoted in Biographia Britannica (18th century); a remembered remark, not his own writing

Q: What causes gravity? In the General Scholium of the Principia (1713) he answers that he has explained the motions of the heavens and the sea by gravity but has not assigned its cause, and that he does not frame hypotheses. That is a paraphrase; the Latin phrase is “hypotheses non fingo”.

Questions to leave out

  • Anything about Einstein's general relativity (1915), which changed how gravity is understood. Newton cannot respond to it.
  • Spaceflight, satellites or the Moon landings, though you can ask him what would happen to a cannonball fired fast enough from a mountain: he drew that thought experiment himself.
  • “What is it like to be a scientist?” The word scientist was coined in 1833. He called himself a natural philosopher.
  • The apple tree at Woolsthorpe that people visit today, or the Newton portraits on later banknotes.

Where to read Newton's papers

Most of his manuscripts are at Cambridge University Library and King's College, Cambridge, with the theological and prophecy papers (the Yahuda collection) at the National Library of Israel. The Newton Project, run from the University of Oxford, has transcribed thousands of pages, and the Cambridge Digital Library shows the originals, including his own annotated copy of the Principia. The Royal Society holds the reflecting telescope story in its early records, and Andrew Motte's 1729 English translation of the Principia is free to read online. For a full life, Richard Westfall's Never at Rest (1980) is the standard biography.

For comparisons, see Newton vs Galileo and the scientific revolution.

Questions people ask

What are good questions to ask Isaac Newton?
Ask about moments with a record behind them: what he worked on during the plague years of 1665 and 1666, what Halley asked him in 1684, why he quarrelled with Hooke and Leibniz, how he caught the counterfeiter William Chaloner at the Mint, and why he kept his religious views secret. Each has answers in his letters and the Principia.
When is the 300th anniversary of Isaac Newton's death?
Newton died on 31 March 1727 by the modern calendar (20 March 1726 in the Old Style calendar then used in England), so the 300th anniversary falls on 31 March 2027. He is buried in Westminster Abbey.
Did an apple really fall on Newton's head?
No early source says it hit him. William Stukeley's memoir, written in 1752, reports that Newton told him in 1726 that watching an apple fall in the garden at Woolsthorpe set him thinking about gravity. The story may be true in that form; the bump on the head is a later embellishment.
Who invented calculus, Newton or Leibniz?
Both, independently. Newton developed his method of fluxions in the mid 1660s but did not publish it; Leibniz published his calculus in 1684. A Royal Society report in 1712 sided with Newton, but Newton wrote much of it himself. Historians today credit both.

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