## Once every decade or so, a film based on numerical ideas attempts to leap into the popular realm. Is it a mathematician’s dream, or their nightmare?

*Warning: spoilers, for this fourteen-year-old film, ahead.*

*Additional warning: the mathematical reasoning displayed in this film should be practiced with caution. Arithmetic operations are used to model many physical processes in the modern world and, as such, should be used justly, unless you want to watch the world burn.*

I** sat down to watch The Number 23 with an emotion that is probably now familiar to all of us in this stay-at-home modern world.** I’m sure there’s a German word that describes the ineffable feeling: “Having run through almost every single thing, on every possible streaming service, including documentaries about the world of competitive poultry breeding and showing in New Zealand, I arrived at that film I always avoided seeing because it sounded just a bit too contrived”. And I found

*The Real Housewives of Sydney*to be vaguely compelling for a time, so you know my where my standards lie.

From a narrative point of view, *The Number 23* begins in a familiar, intrigue-building way. Walter Sparrow (Jim Carrey) is a dog catcher in trouble. It’s all started with a dog called NED, and now Walter Sparrow is being haunted by the number 23 via a book of the same title: *The Number 23* by Topsy Kretts (say that name fast to get a sense of how early the eye-rolling can begin).

This conspiracy is centred around something called the *23 enigma*, which is apparently a ‘real’ thing – or at least the kind of ‘real’ that equates to 30,000 web pages, including a tightly footnoted Wikipedia entry – however, I don’t feel particularly remiss that, as a scientist, I’d never heard of this numerical oddity until I watched this movie. Essentially, it’s the belief that the number 23 has a special significance, above and beyond being a fairly critical natural number if you want to count from 22 to 24. (I’m more familiar with *The 27 Club*; a list of mostly musicians, artists, and actors who died at age 27.)

In a series of unfortunate events (*#jimcarreyjoke*), Sparrow’s wife, Agatha (Virginia Madsen), happens upon Kretts’ book in a second-hand book shop called ‘A Novel Fate’, which really sets the tone for the remainder of the film.

As he begins to read, the book, which is conveniently acted out for us by the film’s primary thespians, becomes intertwined with reality, sort of like if Winona Ryder’s Jo March wrote *Little Women *as an overdramatised yet lacklustre roman noir. The book’s protagonist, Fingerling (Carrey, in his best Nick Cave dress-ups) is a wise-cracking, saxophone-playing, barbed-wire-tribal-tattoo-covered detective who has awkward sex on the floor far too many times for anyone to be comfortable with. It is Fingerling Carrey who leads Sparrow Carrey in his descent into madness via the number 23, which appears everywhere, if – and only if – you’re not just into quickfire mental arithmetic but also ASCRIBING THINGS AN ARBITRARY VALUE.

The *23 enigma* in this film starts by throwing around digits in a way that reminds me of a game you may have played as a kid … where you give the letters of the alphabet numerical values (A = 1, B = 2, C = 3 … Z = 26), add up the ‘value’ of your name and voila! Somehow those numbers had something to do with the person you’re going to marry but I can’t quite remember how.

For example, Walter Paul Sparrow = (23+1+12+20+5+18) + (16+1+21+12) + (19+16+1+18+18+15+23) = (79) + (50) + (110) which, following a method of addition not endorsed by any mathematician anywhere in the world, (7+9) + (5+0) + (1+1+0) = 23. Imagine if people did this in their day-to-day lives: “the sandwich is $10 and the coffee is $4, so you owe me $5”, “the lift car itself weighs about 1200kg and is rated for 900kg, so the motor and counterweight will need to support at least 12kg”. Sparrow’s birthday is 3 February, or 2/3 (= 23) in the US month-day date format. Apparently, his driver’s licence and social security number also add up in this way, he tells his perplexed family.

Consequently, Sparrow finds himself seeing the number 23 everywhere, as well as parallels between his own life and the book. He draws his son into this somewhat misguided world and, to be honest, it’s oddly heart-warming to see a father and son so enthusiastically bonding over their newfound love of incorrectly using mathematical operations.

This film also contains some of those nice tropes we ‘love’ (as in: “I love it when someone opens a medicine cabinet in a horror movie, and there’s a reflection of something bad in the mirror when the door closes”) in films that contain maths: people fervently scribbling numbers and equations on walls, limbs, anything, in their frenzied madness of self-discovery.

My favourite instance of this is the first time we’re drawn inside the *Number 23* book world; Fingerling is learning about the 23 enigma from a character named ‘The Suicide Blonde’ (the flippant treatment of mental health issues in this film is problematic to say the least) and, as she is shouting about how the “f**king number 23” rules her world, there is an equation written in red whiteboard marker on the mirror in front of her:

Do you know what that means? Turns out, as a card-carrying mathematician, I do: in this context, absolutely nothing. Unless she’s trying to calculate the curl of the vector field *G* (that’s a bonus joke for anyone who’s really into vector calculus). Why is it there and what does it have to do with the number 23? Who knows. There’s also a sketch of a cube with the numbers 2, 3, and a scribbled-out triangle (I think?), on the visible sides. But at least we know why *that’s* there (spoiler: it’s 23).

For those who like to press pause repeatedly, and for whom hammering home the message is never enough, we’re very purposely shown a number plate: 023 5HJ; if the first ‘023’ isn’t obvious enough, 5 + H + J = 5 + 8 +10 = 23.

The numbers on the shops that Fingerling is standing in front of are 12 and 110. If you’re the kind of person who ignores zeros as placeholders in the decimal system (would you prefer $11, or $110, in your wallet?) 12 + 11 = 23.

As Sparrow starts to question his own sanity, he takes himself off to room #23 (he refuses room #27) at the King Edward Hotel. When we first see the neon sign for the hotel, the “O” and “T” lights are not working. So in the word ‘hotel’, that’s two broken letters and three illuminated letters: 23. Now, O = 15, and 1 + 5 = 6, and 6 divided by the number of broken letters is 6/2 = 3. Add that to the other broken letter, T = 20, and we get 20 + 3 = 23. It’s interesting how we can make numbers do whatever we want if we try hard enough … for example, the Intergovernmental Panel on Climate Change (IPCC) warns, in their latest report written by an international team of 234 leading scientists and finalised during the 14th Session of Working Group I and 54th Session of the IPCC, that the planet is likely to warm by 1.5℃ in the next decade. Now the number of scientists divided by expected warming is 234/1.5 = 156 and 1 + 5 + 6 = 12 and 1 + 2 = 3, but the absolute difference in ‘Sessions’ is 54 – 14 = 40 and 40 + 3 = 43, which is interesting because ‘climate change is a hoax’ = (3 + 12 + 9 + 13 + 1 + 20 + 5) + (3 + 8 + 1 + 14 + 7 + 5) + (9 + 19) + (1) + (8 + 15 + 1 + 24) = (63) + (38) + (28) + (1) + (48), which becomes (6+3) + (3+8) + (2+8) + (1) + (4+8) = 43. (Note: the author does not truly believe that climate change is a hoax, please don’t write in.)

Sparrow sees a 23-oxy sign affixed to a building, which is actually a National Fire Protection Association (NFPA) panel alerting firefighters to the dangers that may lie inside (in this case, it’s a hazardous oxidiser that a shock or heat may detonate).

The PO Box at which Sparrow and his family stalk an old man (after sending the old man 23 boxes of what looks like packing peanuts) is ‘PO Box 977’ and you know the drill.

The trunk of secrets that will later reveal the truth to us, reads “SPARROW. W. CASE NO. 85307” …

Fabrizia has 23 pairs of shoes. The film was even released in the US on 23 February, 2007.

I would say that the list of these ‘coincidences’ is endless, but I wouldn’t be surprised if there ended up being twenty-three of them in total.

It’s all a bit much. But as someone who thinks the way we use numbers is actually quite important, the point of no return comes when we start including the number 32 in this long line of conspiracies because 32 is 23 “backwards”. “No officer, I wasn’t speeding, I was going 52 km/h in a school zone.[1]” That’s not really how maths works.

In the end – not that I was particularly fussed by this point – Sparrow is actually a murderer who totally forgot about it, despite having written his confession in the form of the suicide note-cum-book he would later read. And it was all brought back to Sparrow’s attention by the magical dog and guardian of the dead who led him to the grave of the person he killed but totes forgot about: NED = 14 + 5 + 4 = 23.

My mother’s birthday is February 3^{rd} too. I calculated her name and, luckily, it’s a hefty 40, so the good news is, she’s probably not a cursed, secret ex-murderer. But remind me to ask her if she’s read any good books lately.

And please, I implore you – don’t try this kind of dangerous, civilisation-crumbling maths at home.

[1] This joke only works in South Australia.

Originally published by Cosmos as A mathematician watches The Number 23

### Sophie Calabretto

Sophie Calabretto is a mathematician specialising in fluid mechanics. She is Honorary Senior Lecturer at Macquarie University and Honorary Associate Professor, at the ACE Research Group, University of Leicester.