Free Republic
Browse · Search
General/Chat
Topics · Post Article

Skip to comments.

How To Marry The Right Girl: A Mathematical Solution by the Great Astronomer, Johannes Kepler
NPR ^ | 05/15/2014 | Robert Krulwich

Posted on 05/15/2014 7:24:11 PM PDT by SeekAndFind

Poor, confused Johannes Kepler.

Robert Krulwich/NPR

Poor Johannes Kepler. One of the greatest astronomers ever, the man who figured out the laws of planetary motion, a genius, scholar and mathematician — in 1611, he needed a wife. The previous Mrs. Kepler had died of Hungarian spotted fever, so, with kids to raise and a household to manage, he decided to line up some candidates — but it wasn't going very well.

Being an orderly man, he decided to interview 11 women. As Alex Bellos describes it in his new book The Grapes of Math, Kepler kept notes as he wooed. It's a catalog of small disappointments. The first candidate, he wrote, had "stinking breath."

The first candidate had "stinking breath."

Robert Krulwich/NPR

The second "had been brought up in luxury that was above her station" — she had expensive tastes. Not promising.

The second had expensive tastes.

Robert Krulwich/NPR

The third was engaged to a man — definitely a problem. Plus, that man had sired a child with a prostitute. So ... complicated.

The third was engaged to someone else and already had a baby.

Robert Krulwich/NPR

The fourth woman was nice to look at — of "tall stature and athletic build" ...

The fourth woman was too tall.

Robert Krulwich/NPR

... but Kepler wanted to check out the next one (the fifth), who, he'd been told, was "modest, thrifty, diligent and [said] to love her stepchildren," so he hesitated. He hesitated so long, that both No. 4 and No. 5 got impatient and took themselves out of the running (bummer), leaving him with No. 6, who scared him. She was a grand lady, and he "feared the expense of a sumptuous wedding ... "

No. 6 scared him.

Robert Krulwich/NPR

The seventh was very fetching. He liked her. But he hadn't yet completed his list, so he kept her waiting, and she wasn't the waiting type. She rejected him.

He liked the seventh but she rejected him. i i

Robert Krulwich/NPR

He liked the seventh but she rejected him.

Robert Krulwich/NPR

The eighth he didn't much care for, though he thought her mother "was a mostly worthy person ... "

The eighth he didn't much care for.

Robert Krulwich/NPR

The ninth was sickly, the 10th had a shape not suitable "even for a man of simple tastes," and the last one, the 11th, was too young. What to do? Having run through all his candidates, totally wooed-out, he decided that maybe he'd done this all wrong.

"Was it Divine Providence or my own moral guilt," he wrote, "which, for two years or longer, tore me in so many different directions and made me consider the possibility of such different unions?"

Game On

What Kepler needed, Alex Bellos writes, was an optimal strategy — a way, not to guarantee success, but to maximize the likelihood of satisfaction. And, as it turns out, mathematicians think they have such a formula.

It works any time you have a list of potential wives, husbands, prom dates, job applicants, garage mechanics. The rules are simple: You start with a situation where you have a fixed number of options (if, say, you live in a small town and there aren't unlimited men to date, garages to go to), so you make a list — that's your final list — and you interview each candidate one by one. Again, what I'm about to describe doesn't always produce a happy result, but it does so more often than would occur randomly. For mathematicians, that's enough.

They even have a name for it. In the 1960s it was called (a la Kepler) "The Marriage Problem." Later, it was dubbed The Secretary Problem.

Kepler considers "The Marriage Problem."

Robert Krulwich/NPR

How To Do It

Alex writes: "Imagine that you are interviewing 20 people to be your secretary [or your spouse or your garage mechanic] with the rule that you must decide at the end of each interview whether or not to give that applicant the job." If you offer the job to somebody, game's up. You can't go on and meet the others. "If you haven't chosen anyone by the time you see the last candidate, you must offer the job to her," Alex writes (not assuming that all secretaries are female — he's just adapting the attitudes of the early '60s).

So remember: At the end of each interview, you either make an offer or you move on.

If you don't make an offer, no going back. Once you make an offer, the game stops.

According to Martin Gardner, who in 1960 described the formula (partly worked out earlier by others), the best way to proceed is to interview (or date) the first 36.8 percent of the candidates. Don't hire (or marry) any of them, but as soon as you meet a candidate who's better than the best of that first group — that's the one you choose! Yes, the Very Best Candidate might show up in that first 36.8 percent — in which case you'll be stuck with second best, but still, if you like favorable odds, this is the best way to go.

Why 36.8 percent? The answer involves a number mathematicians call "e" – which, reduced to a fraction 1/e = 0.368 or 36.8 percent. For the specific details, check here, or Alex's book, but apparently this formula has proved itself over and over in all kinds of controlled situations. While it doesn't guarantee happiness or satisfaction, it does give you a 36.8 percent chance — which, in a field of 11 possible wives — is a pretty good success rate.

Try It, Johannes ...

What would have happened if Johannes Kepler had used this formula? Well, he would have interviewed but made no offers to the first 36.8 percent of his sample, which in a group of 11 ladies means he'd skip past the first four candidates. But the moment he'd met somebody (starting with lady No. 5) that he liked better than anyone in the first group, he'd have said, "Will you marry me?"

In real life, after a period of reflection, Johannes Kepler re-wooed and then married the fifth woman.

The way Alex figures it, if Kepler had known about this formula (which today is an example of what mathematicians call optimal stopping), he could have skipped the last batch of ladies — the sickly one, the unshapely one, the too-young one, the lung-disease one — and, all in all, "Kepler would have saved himself six bad dates."

Instead, he just followed his heart (which, of course, is another tolerable option, even for great mathematicians). His marriage to No. 5, by the way, turned out to be a very happy one.


TOPICS: Science; Society
KEYWORDS: kepler; marriage; mathematics
Navigation: use the links below to view more comments.
first 1-2021-40 next last

1 posted on 05/15/2014 7:24:11 PM PDT by SeekAndFind
[ Post Reply | Private Reply | View Replies]

To: SeekAndFind
I would rather calculate the motions of the planets by hand, with pencil and paper, than attempt dating again.

/johnny

2 posted on 05/15/2014 7:28:37 PM PDT by JRandomFreeper (Gone Galt)
[ Post Reply | Private Reply | To 1 | View Replies]

To: SeekAndFind

How To Marry The Right Girl:
Sorry guys, I’m already married!


3 posted on 05/15/2014 7:34:28 PM PDT by Isabel2010
[ Post Reply | Private Reply | To 1 | View Replies]

To: JRandomFreeper

“I would rather calculate the motions of the planets by hand, with pencil and paper, than attempt dating again. “

Yeah, you can make a pretty good cor arranged marriages at times. Though that would not have worked for me


4 posted on 05/15/2014 7:34:55 PM PDT by Fai Mao (Genius at Large)
[ Post Reply | Private Reply | To 2 | View Replies]

To: SeekAndFind
Since when is NPR concerned about marrying the right “girl?” That is racist, homophobic, hetero phobic, trens-genderphobic........ Another reason this worthless piece of dung should be denied funding. Why is the public forced to essentially provide a job for a network of fools that cannot make it on their own? If Fox goes down, should the public bail them out? It's an upside down world.
5 posted on 05/15/2014 7:38:30 PM PDT by Fungi
[ Post Reply | Private Reply | To 1 | View Replies]

To: SeekAndFind

When I met my wife, I noticed she put out frequently, liked professional wrestling, played video games, had a great body, was smart, and wasn’t infatuated with money or possessions.

It didn’t take long to put a ring on her finger - 3 kids later we’re still doing fine.


6 posted on 05/15/2014 7:41:50 PM PDT by struggle
[ Post Reply | Private Reply | To 1 | View Replies]

To: Fai Mao
No. No more wives. I've got the house just like I want it, and can find everything. ;)

/johnny

7 posted on 05/15/2014 7:42:27 PM PDT by JRandomFreeper (Gone Galt)
[ Post Reply | Private Reply | To 4 | View Replies]

To: SeekAndFind

e provides the best selection again


8 posted on 05/15/2014 7:44:28 PM PDT by Nifster
[ Post Reply | Private Reply | To 1 | View Replies]

To: JRandomFreeper

I was happily married for many years. I’m widowed now. Miss the wife, but, really am not eager to get married again. The kids are raised and on their own. It’s a new stage of life, and I just don’t feel the need to think about marriage again.

I actually am seeing someone, and we enjoy each other, but, we’ve both raised families, and both are happy with how things are.


9 posted on 05/15/2014 7:48:41 PM PDT by Dilbert San Diego
[ Post Reply | Private Reply | To 7 | View Replies]

To: struggle
I noticed she put out frequently

"Put out" .... ? Can you find a less tacky expression when talking about your wife?

10 posted on 05/15/2014 7:51:00 PM PDT by Lizavetta
[ Post Reply | Private Reply | To 6 | View Replies]

To: SeekAndFind

My formula was:
1. Find one who seems crazy enough to say yes
2. Marry her.

We hit 25 years next month - gets better every year


11 posted on 05/15/2014 7:51:41 PM PDT by Gil4 (And the trees are all kept equal by hatchet, ax and saw)
[ Post Reply | Private Reply | To 1 | View Replies]

To: SeekAndFind

For me the math’s simple....36/22/34....salary,%75K (min)...net worth,%500K (min).


12 posted on 05/15/2014 7:52:00 PM PDT by Gay State Conservative (Rat Party Policy:Lie,Deny,Refuse To Comply)
[ Post Reply | Private Reply | To 1 | View Replies]

To: SeekAndFind

Reminds me of that joke about a woman seeking the ideal husband in a multi-floor department store, with each floor featuring a more ideal husband, with more winsome qualities, and even that candidate is not good enough, go on to the next floor up....


13 posted on 05/15/2014 7:52:19 PM PDT by thecodont
[ Post Reply | Private Reply | To 1 | View Replies]

To: Lizavetta

>>”Put out” .... ? Can you find a less tacky expression when talking about your wife?

Ok, we had sex a lot.


14 posted on 05/15/2014 7:52:36 PM PDT by struggle
[ Post Reply | Private Reply | To 10 | View Replies]

To: JRandomFreeper

Somebody said: “I’m not going to marry again. I’ll just find a woman I hate, and buy her a house...”


15 posted on 05/15/2014 7:54:05 PM PDT by jonno (Having an opinion is not the same as having the answer...)
[ Post Reply | Private Reply | To 7 | View Replies]

To: struggle

Better. Thank you.


16 posted on 05/15/2014 7:54:26 PM PDT by Lizavetta
[ Post Reply | Private Reply | To 14 | View Replies]

To: Lizavetta

Would you prefer he said she banged like a screen door?


17 posted on 05/15/2014 8:03:18 PM PDT by meatloaf (Impeach Obama. That's my New Year's resolution.)
[ Post Reply | Private Reply | To 10 | View Replies]

To: SeekAndFind
why does the term equally yoked come to mind?
18 posted on 05/15/2014 8:03:19 PM PDT by Chode (Stand UP and Be Counted, or line up and be numbered - *DTOM* -vvv- NO Pity for the LAZY - 86-44)
[ Post Reply | Private Reply | To 1 | View Replies]

To: JRandomFreeper

You found the wrong ones because you picked the wrong ones. :)


19 posted on 05/15/2014 8:05:26 PM PDT by Shimmer1
[ Post Reply | Private Reply | To 2 | View Replies]

To: Lizavetta; struggle
"Put out" .... ? Can you find a less tacky expression when talking about your wife?

I was hoping she was a first baseman...

20 posted on 05/15/2014 8:12:45 PM PDT by FredZarguna (Das ist nicht nur nicht richtig, es ist nicht einmal falsch!)
[ Post Reply | Private Reply | To 10 | View Replies]


Navigation: use the links below to view more comments.
first 1-2021-40 next last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
General/Chat
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson