Mark Haddon - The Curious Incident of the Dog in the Night-Time

Lots of people wrote to the magazine to say that Marilyn vos Savant was wrong, even when she explained very carefully why she was right. Of the letters she got about the problem, 92% said that she was wrong and lots of these were from mathematicians and scientists. Here are some of the things that they said:

I’m very concerned with the general public’s lack of mathematical skills. Please help by confessing your error.

There is enough mathematical illiteracy in this country, and we don’t need the world’s highest IQ propagating more. Shame!

I am in shock that after being corrected by at least three mathematicians, you still do not see your mistake.

I am sure you will receive many letters from high school and college students. Perhaps you should keep a few addresses for help with future columns.

You are utterly incorrect… How many irate mathematicians are needed to get you to change your mind?

If all those Ph.D.’s were wrong, the country would be in very serious trouble.

But Marilyn vos Savant was right. And here are 2 ways you can show this.

Firstly you can do it by maths like this:

Let the doors be called X, Y and Z.

Let Cx be the event that the car is behind door X and so on.

Let Hx be the event that the host opens door X and so on.

Supposing that you choose door X, the possibility that you win a car if you then switch your choice is given by the following formula

P(Hz ^ Cy) + P(Hy ^ Cz)

= P(Cy)·P (Hz : Cy) + P(Cz)·P(Hy : Cz)

= (1/3 · 1) + (1/3 · 1) = 2/3

The second way you can work it out is by making a picture of all the possible outcomes like this:

So if you change, 2 times out of 3 you get a car. And if you stick, you only get a car 1 time out of 3.

And this shows that intuition can sometimes get things wrong. And intuition is what people use in life to make decisions. But logic can help you work out the right answer.

It also shows that Mr. Jeavons was wrong and numbers are sometimes very complicated and not very straightforward at all. And that is why I like The Monty Hall Problem.

103.When I got home Rhodri was there. Rhodri is the man who works for Father, helping him do heating maintenance and boiler repair. And he sometimes comes round to the house in the evening to drink beer with Father and watch the television and have a conversation.

Rhodri was wearing a pair of white dungarees which had dirty marks all over them and he had a gold ring on the middle finger of his left hand and he smelled of something I do not know the name of which Father often smells of when he comes home from work.

I put my licorice laces and my Milky Bar in my special food box on the shelf, which Father is not allowed to touch because it is mine.

Then Father said, “And what have you been up to, young man?”

And I said, “I went to the shop to get some licorice laces and a Milky Bar.”

And he said, “You were a long time.”

And I said, “I talked to Mrs. Alexander’s dog outside the shop. And I stroked him and he sniffed my trousers.” Which was another white lie.

Then Rhodri said to me, “God, you do get the third degree, don’t you?”

But I didn’t know what the third degree was.

And he said, “So, how are you doing, captain?”

And I said, “I’m doing very well, thank you,” which is what you’re meant to say.

And he said, “What’s 251 times 864?”

And I thought about this and I said, “216,864.” Because it was a really easy sum because you just multiply 864 * 1,000,which is 864,000.Then you divide it by 4, which is 216,000,and that’s 250 * 864. Then you just add another 864onto it to get 251 * 864. And that’s 216,864.

And I said, “Is that right?”

And Rhodri said, “I haven’t got a bloody clue,” and he laughed.

I don’t like it when Rhodri laughs at me. Rhodri laughs at me a lot. Father says it is being friendly.

Then Father said, “I’ll stick one of those Gobi Aloo Sag things in the oven for you, OK?”

This is because I like Indian food because it has a strong taste. But Gobi Aloo Sag is yellow, so I put red food coloring into it before I eat it. And I keep a little plastic bottle of this in my special food box.

And I said, “OK.”

And Rhodri said, “So, it looks like Parky stitched them up, then?” But this was to Father, not to me.

And Father said, “Well, those circuit boards looked like they’d come out of the bloody ark.”

And Rhodri said, “You going to tell them?”

And Father said, “What’s the point? They’re hardly going to take him to court, are they?”

And Rhodri said, “That’ll be the day.”

And Father said, “Best to let sleeping dogs lie, I reckon.”

Then I went into the garden.

Siobhan said that when you are writing a book you have to include some descriptions of things. I said that I could take photographs and put them in the book. But she said the idea of a book was to describe things using words so that people could read them and make a picture in their own head.

And she said it was best to describe things that were interesting or different.

She also said that I should describe people in the story by mentioning one or two details about them so that people could make a picture of them in their head. Which is why I wrote about Mr. Jeavons’s shoes with all the holes in them and the policeman who looked as if he had two mice in his nose and the thing Rhodri smelled of but I didn’t know the name for.

So I decided to do a description of the garden. But the garden wasn’t very interesting or different. It was just a garden, with grass and a shed and a clothesline. But the sky was interesting and different because usually skies look boring because they are all blue or all gray or all covered in one pattern of clouds and they don’t look like they are hundreds of miles above your head. They look like someone might have painted them on a big roof. But this sky had lots of different types of clouds in it at different heights, so you could see how big it was and this made it look enormous.

Furthest away in the sky were lots of little white clouds which looked like fish scales or sand dunes which had a very regular pattern.

Then next furthest away and to the west were some big clouds which were colored slightly orange because it was nearly evening and the sun was going down.

Then closest to the ground was a huge cloud which was colored gray because it was a rain cloud. And it was a big pointy shape and it looked like this:

And when I looked at it for a long time I could see it moving very slowly and it was like an alien spaceship hundreds of kilometers long, like in Dune or Blake’s 7 or Close Encounters of the Third Kind , except that it wasn’t made of solid material, it was made of droplets of condensed water vapor, which is what clouds are made of.

And it could have been an alien spaceship.

People think that alien spaceships would be solid and made of metal and have lights all over them and move slowly through the sky because that is how we would build a spaceship if we were able to build one that big. But aliens, if they exist, would probably be very different from us. They might look like big slugs, or be flat like reflections. Or they might be bigger than planets. Or they might not have bodies at all. They might just be information, like in a computer. And their spaceships might look like clouds, or be made up of unconnected objects like dust or leaves.