In (hypothetical) conversation with Sir Isaac Newton

E&T: Good morning, Sir Isaac. Let’s get a few terms clear from the start. In the 21st century you’re often hailed as ‘Britain’s greatest ever scientist.’ You’re shaking your head. Please explain.

Sir Isaac Newton: There are factual and linguistic inaccuracies in the premise of your question, sir. I’m not entirely sure exactly what you mean by the word ‘Britain’ here, but if you are referring to the Kingdom of Great Britain, then that didn’t come into being until 1707, following the Acts of Union, which was towards the end of my terrestrial life. So, if you wish to be correct, since I was born in the hamlet of Woolsthorpe-by-Colsterworth in the county of Lincolnshire, the term you should apply to my nationality is ‘English.’ Similarly, the word ‘scientist’ was never used in the way you mean it until the 19th century, when it was coined by William Whewell, Master of Trinity College, Cambridge – my old college in fact – where I started off as a subsizar (what 21st century folk would call ‘working your way through college’). But I digress. Before the ‘natural sciences’ became recognised, people like me (although there weren’t very many to fall into that category) called ourselves ‘natural philosophers.’

E&T: You’re best known for your three physical laws that established the foundation for classical mechanics. But you’re also remembered for the ‘apple incident.’ Is there any truth in that?

Sir Isaac Newton: Absolutely. I have often gone on record as saying that I was inspired to formulate my theory of gravitation by watching an apple fall from a tree. But the story has only become famous because my niece Catherine Barton once gave an account of the matter to the French writer Voltaire, who then reproduced the story in his 1727 Essay on Epic Poetry, in which he says: “Sir Isaac Newton walking in his gardens, had the first thought of his system of gravitation, upon seeing an apple falling from a tree.” My friend William Stukely – who was one of the early archaeologists at Stonehenge – recounts it in a more scientific way, when he writes in his Memoirs of Sir Isaac Newton’s Life that I considered the questions: “why should it not go sideways, or upwards? but constantly to the earths centre?” But the whole idea that I ‘invented’ gravity after being struck on the head by an apple is apocryphal. Also, for some reason people still debate which was the actual tree and where the event took place. I’m told there’s even a nursery in Kent that will supply you with a graft from one of the descendants of the tree. I can’t quite work out why you’d want one, because the fruit itself actually looks like a pear and is a very poor-quality cooking apple of no culinary significance whatsoever.

E&T: So, you’re an English natural philosopher. Is there any latitude to call you an engineer?

Sir Isaac Newton: Good Lord, no… never used the term. In fact, it didn’t really take off as a descriptor for people who solve engineering problems until the 19th century, when ‘engineers’ like Isambard Kingdom Brunel were building bridges and railways all over the place. But we knew the Latin word ingenium – what you might translate as ‘engine’ – that since the Middle Ages had the meaning, “innate quality, especially mental power, hence a clever invention.” Of course, a lot of these terms became more rigid in the mid-18th century, when the lexicographer Samuel Johnson published his A Dictionary of the English Language. But in my day, we used Latin in any case. My most famous book – Philosophiæ Naturalis Principia Mathematica – was written in Latin. That’s the one where I state the laws of motion, the law of universal gravitation and derivations about Kepler’s laws of planetary motion. It had some enthusiastic reviews too, especially from the French mathematician Alexis Clairaut who, in my view, rather wisely wrote in his paper Du systeme du monde, dans les principes de la gravitation universelle that I had, “spread the light of mathematics on a science which up to then had remained in the darkness of conjectures and hypothesis.” Which sort of became my catchphrase – hypothesis non fingo – meaning ‘I feign no hypothesis.’ Catchy, isn’t it?

E&T: Why don’t we move on to telling us something of your early life?

Sir Isaac Newton: Although Voltaire said that I wasn’t “subject to the common frailties of mankind,” I did once threaten to burn my mother and stepfather alive. My real father died before I was born and he was replaced in my mother’s affections by the loathsome Reverend Barnabus Smith, so I was packed off to live with my grandmother. It was an unpleasant time, especially as my mother wanted me to become a farmer. But eventually I was sent to school, where I learned Latin, Greek and mathematics, and where I was bullied. But I got my revenge by becoming the top scholar at the school and spent my time building sundials and making models of windmills. I went up to Trinity College in 1661, where we were taught Aristotle, but I soon got into the ideas of the more modern philosophers such as Descartes – ‘I think, therefore I am’ – and astronomers like Galileo. By 1665, I’d developed a mathematical theory that was to evolve into calculus. But then the university closed down for two years because of the Great Plague, and so I went back to Lincolnshire, where I worked further on calculus and the law of gravitation. When I returned to Cambridge, I was elected Fellow of Trinity. But in those days, you needed to be ordained as a priest to be a fellow. For eight years I deferred ordination, but it all came to a head in 1675, and I only managed to secure an exemption when King Charles II stepped in.

E&T: Before we go on with your academic career, there’s a very strong rumour going about these days that you actually predicted the end of the world?

Sir Isaac Newton: This is all a bit of a mix up, really. Now, it is true that I wrote a manuscript in 1704 – which, in my defence was never intended for publication – in which I mention the year 2060. But, I did not state that it was an apocalyptic prediction. In fact, I was completely against setting a date for the end of days. It’s one of those moments where people haven’t read the text properly. Let me quote the part that people always conveniently forget. “This I mention not to assert when the time of the end shall be, but to put a stop to the rash conjectures of fanciful men who are frequently predicting the time of the end, and by doing so bring the sacred prophesies into discredit as often as their predictions fail. Christ comes as a thief in the night, and it is not for us to know the times and seasons which God hath put into his own breast.”

E&T: Well, I’m glad we cleared that up. Let’s get back to your career. Tell us a bit more about your book Principia?

Sir Isaac Newton: The main point on which Mathematical Principles of Natural Philosophy, to give its title in English, is remembered today is that it published the three physical laws of classical mechanics, that are now known as Newton’s laws of motion. Put simply, they say the following. The First Law states: “A body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force.” The Second Law describes what happens to a massive body when it is acted upon by an external force. It states: “The force acting on an object is equal to the mass of that object times its acceleration.” And the third states that for, “every action, there is an equal and opposite reaction.” It’s been said many times that my book is one of the most important works in the history of science and that, “it so far exceeded anything that had ever gone before that it stood alone as the ultimate exemplar of science generally.” But as I said in my (much misunderstood) letter of 1676 to Robert Hooke, if I have seen further it is by standing on the shoulders of giants.

E&T: Didn’t that quotation appear on a coin?

Sir Isaac Newton: It eventually resurfaced on the milled edge of the 2015 £2 coin, which is especially pleasing for me, as I spent the last thirty years of my career as Master of the Mint. I took up the government office appointment just after the Great Recoinage of 1696, which was an attempt to upgrade the nation’s coin stock, some twenty percent of which was counterfeit. Which meant that I spent a great deal of time prosecuting criminals. You would expect that someone so senior in the world of finance would have a good head for money, but I lost £20,000 when the South Sea Bubble burst in 1720… more than £4m in today’s money.

E&T: Had they been around in your day, do you think you would have won a Nobel Prize?

Sir Isaac Newton: Well, if they can dish one out to Bob Dylan, then I suppose anything’s possible. But, you see, the passage of time hasn’t been kind to every aspect of my reputation, especially when it comes to my adventures in alchemy or, as it was often called in seventeenth-century England, ‘chymistry.’ To me, the widespread criticism levelled against me seems outrageously biased. This is because I wrote more than ten million words in my entire career, and only one million of them was about my search for the philosopher’s stone, which I understand is more than tolerated when it comes to the Harry Potter franchise, which seems to turn everything into gold. Perhaps there was some substance to my ‘muddling with alchemy’ as one American writer put it, after all. But there are other ideas that with hindsight I can’t help wishing hadn’t surfaced at all. I don’t think that modern medicine will take very seriously my proposed cures for the Great Plague caused by the Yersinia pestis bacterium that was so enthusiastically reported in the Guardian newspaper in the midst of the coronavirus pandemic: “The best is a toad suspended by the legs in a chimney for three days, which at last vomited up earth with various insects in it, on to a dish of yellow wax, and shortly after died. Combining powdered toad with the excretions and serum made into lozenges and worn about the affected area drove away the contagion and drew out the poison.” It seemed like a good idea at the time.

E&T: Birthday and Christmas on the same day: that’s a bit unfortunate, isn’t it?

Sir Isaac Newton: It has certainly created one or two controversies over the years. I believe the 21st century American celebrity astrophysicist Neil DeGrasse Tyson caused something of a commotion when he tweeted on Christmas Day in 2014: “On this day long ago, a child was born who, by age 30, would transform the world. Happy Birthday Isaac Newton b. Dec 25, 1642.” On the face of it, this is nothing compared with some of my encrypted manuscripts that go a long way to explaining why I needed the exemption from the priesthood granted by the king. Had my views been known at the time I’d have been called a heretic. None of which seemed to bother the poet Alexander Pope who wrote my epitaph as follows:

E&T: ‘Nature and nature’s laws lay hid in night; God said “Let Newton be” and all was light.’

Happy Christmas, everyone!