Okay, so here's another example of mechanism design and
I'm going to basically break it into two bits.
I'm going to see if I can remind you of a particular mechanism design that
somebody famous once used in a story told in the Bible, and
then point out that that's kind of ridiculous.
>> [LAUGH] >> And then we're going to
come up with something slightly better.
Does that seem fair?
>> I'm interested to see this, sure.
>> Okay, so this is the story of King Solomon.
I drew King Solomon to look remarkably like Curly.
>> Fun.
>> Yeah. >> I get to be King Solomon, finally,
after all this time >> You get to be King Solomon.
So do you remember the story of King Solomon?
>> Yeah, he was wise.
>> Okay, okay, let's go with that.
So then tell me the story of King Solomon and the two women and the baby.
>> All right, so once upon a time King Solomon was hanging around on his
throne doing kingly things and he would answer questions for
the various people in the country that he ruled, Judah, maybe?
>> Sure, let's go with that.
>> But he was known for being very wise, so
people would come up to him with very difficult problems.
So one of the difficult problems was two women came to him with a baby and
each of the women claimed the baby was her baby, and
they could not come to any kind of agreement.
One of them it was actually the baby, the other one was someone who really
wanted a baby, couldn't have a baby and then took someone else's baby.
And so this is not the sort of thing you want to get wrong,
giving somebody's baby to somebody who's not their mom.
>> Right, so, let's see.
So there are two women,
we gotta give them names because I'm having a hard time keeping track.
So, let's just call them A and B.
A for Alice and B for- >> Bob.
>> Bob. That makes perfect sense.
>> Wait, no, Beth.
>> Beth, okay, so Alice and Beth.
And then there's a baby.
And so Alice comes to King Solomon, says Beth stole my baby.
And then Beth comes to King Solomon and says, Alice stole my baby.
And then the baby just goes, ga, because that's what babies do.
See this little curly hair thing?
>> Yeah, that's cool.
>> And now King Solomon does what?
>> So King Solomon checks whether the baby is named A or B and then
can actually trace the genetic roots of the baby back to the appropriate mother.
>> No, that was an episode of CSI.
What does the story claim happened?
>> Yes, I'm sorry.
So King Solomon says, all right, I've thought about this a lot and
I've decided that the only fair way of dividing up the baby is
by dividing up the baby, giving half to A and half to B.
And so that was what he claims he's going to do, and he calls for his royal
sword person to bring a sword and he gets ready to cut the baby in half,
at which point A- >> [LAUGH] I recognize that royal sword.
[LAUGH] It's a Jedi.
All right, so the royal sword person says, okay, I will
bring you the royal sword, and Solomon gets ready to cut the baby in half.
And suddenly woman A cries out, no, don't do it.
B can have the baby.
>> No.
>> Yes.
>> And so B gets to keep the baby.
>> I don't think that's what happened.
>> No, so then King Solomon says aha, I set this up all along.
I never really was going to kill the baby, let's say.
And instead what I wanted to find out is who really cared for the baby,
this particular baby, and that would be the particular baby's actual mother.
So the thought was that the mom would rather have the baby live and
be with a different mom than be sliced in half,
which would probably complicate the baby's life.
>> Yeah, actually I think it would simplify the baby's life, but
okay, I'm with you on that, right.
And then King Solomon could just determine that, in fact,
A was the mother.
>> And, yes, sewed the baby back up and gave the baby to A and sent B to prison?
>> I don't remember. >> I don't know.
Maybe he had a baby with B for B's sake.
I don't know.
That's not really part of the story in my head.
The point, A leaves with the baby, A is happy.
B is disappointed but not so
disappointed because there's plenty of other babies to steal.
>> Right, and then of course there's the poor swordsman who didn't even
get to cut up a baby.
>> [LAUGH] >> Okay, so this is-
>> He does look disappointed.
>> I do, or he does, sorry.
He does look very, very disappointed.
Very sad, in fact there's a single tear.