# Practice English Speaking&Listening with: How a mathematician dissects a coincidence

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What if you could analyze the odds behind fairy tale coincidences that people forward

in email?

Like the twins who died on the same day, or the woman who won the lottery four times.

It's hard not to share the amazement yourself, but there's always more than meets the eye.

So with any of these stories, what you are told is the outer shell.

Think of it as a walnut shell, or I like to think of it as a Russian Troika

doll, and you have to try to understand what is behind that shell or the first doll.”

Thats Joseph Mazur, and hes not a folklorist.

Or a novelist.

My position is Professor of Mathematics, Emeritus, at Marlboro

College.”

How a mathematician approaches stories like those emails can teach us something about

the coincidences in our lives.

So lets tell a story.

In 1929, an American named Anne Parrish went to Paris with her husband (thats why youre

hearing this French-sounding music).

On one sunny June Sunday, they went to mass at Notre Dame.

They visited the bird market.

They had lunch at Deux Magots.

And Anne went for a stroll.

She ended up at a book stall along the Seine and found

Helen Woods childrens book, “Jack Frost and Other Stories.”

She haggled, but it was worth a franc because it had been her favorite book as a child growing

up in America.

She rushed back to her husband to show him.

He turned the pages.

And he found a childs writing scrawled in the front:

Anne Parrish, 209 North Weber Street, Colorado Springs

That book she bought, an ocean away from home was the very same book shed cherished as

a child.

How could that be anything but fate?

What youre doing is youre looking for the hidden variables.

Youre never told, in the initial story, the hidden variables.”

I started to dig, and I looked into how could that book have gotten to the stall at

that particular time, just when Anne Parrish was walking through the stalls.

How is that possible?”

When you start to dig, you find biographies.”

Anne Parrish wasnt just a random person.

Her mother was friends with Mary Cassatt, the famous impressionist painter who moved

to Paris.

That could easily be how the book traveled across the Atlantic - through Mary.

But Anne Parrishs husband is also a key detail.

Charles Corliss is important in this story.

In this case he happened to be a very wealthy industrialist.”

That wealth made it more likely for Anne Parrish to do what most Americans of the time didnt

sip wine near the Seine, after a 5 day boat trip all the way to Europe.

And Paris was one of the most likely destinations.

Mary Cassat died in 1926, just three years before Anne visited Paris.

Her estate was probably liquidated, meaning Annes book went on the market.

And for English books in Paris, sellers didnt have many options.

What are the book stores in Paris?

There are only two in those years: It was Shakespeare & Company and the Paris book stalls.”

Another missing detail?

Anne Parrish was a childrens book author herself.

So that was the first section shed check when browsing books.

With all these facts together, you can start to make some estimates.

How likely is it that Anne would go to Paris in 1929?

Joe Mazur guesses .1 - a tenth.

He looked at Annes actual travel records and saw that she and her husband went to Paris

every two years, like clock work.

Ten to one odds shed go to Paris in 1929 is actually pretty conservative.

The likelihood of her visiting bookstalls?

Conservatively its .3.

She was an author on a long trip!

Theres definitely a one in three chance shed browse for some books.

And the likelihood the book would be in those stalls in the first place?

With all those factors together, its probably .01 - one in a hundred.

Multiply them out, and the odds in favor of her finding that book arent a miracle.

The odds for getting a four of a kind in poker?

4,164 to 1.

I could be dealt that in, lets say an hours worth of playing poker.”

Yes, Im getting numbers, but theyre very approximate numbers.

These are stories that are human stories.

If you start to mathematize these stories, you are breaking it down too far and you are

approximating things that probably are not really true..”

I make approximations, but deep down in the set of Russian Troika dolls, its endless.

You dont get the real kernel doll that doesnt open any more.“

In these stories, those kernel dolls keep opening and opening.

And, I mean, Im not sure it goes to infinity, but it surely goes very deep.”

The most important variable might be if youre curious enough to open the first one.

Thanks a lot to Joe Mazur for talking to me about his book, and thanks to Alexander Woollcott,

who wrote the New Yorker article that gave us Anne Parrishs story.

So Ill close this video the same way he closed that 1932 article: “Somewhere in

fahtomless space a star chuckledchuckled and skipped in its course.”

Good stuff, Alexander.

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