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# Newcombs paradox. What would you do?

Thu 30 Dec, 2004 11:52 pm
The famous problem goes like this:

A being (God, an alien, a supercomputer...) who can predict what humans will choose in a given circumstance. This being has to boxes to give to humans. Box A always holds \$1,000 and Box B may or may not have \$1,000,000.

The being then tells you:

You have two choices. One is to take both boxes and keep their contents. But if I expected you to do this, I have left B empty. You get only \$1000.
Your other choice is to take only box B. If I expected you to do this, I have put a million dollars in B. You get it all.

The being puts the content on the boxes and then he leaves to have no contact whatsoever with you. You will have to make the choice the next day.

Quote:

Well, obviously you should take only Box B, right? For if this is your choice, the Being has almost certainly predicted it and put \$1 million in Box B. If you were to take both boxes, the Being would almost certainly have anticipated this and left Box B empty.

But wait a minute. The Being made his prediction yesterday. He either put \$1 million in Box B, or he didn't. If it's there, it's not going to vanish just because you choose to take both boxes; if it's not there, it's not going to materialize suddenly just because you choose only Box B. Whatever the Being's prediction, you are guaranteed to end up \$1,000 richer if you choose both boxes.

So, what would you choose and why?

What would you choose if Box A held \$1 instead?
What if it held \$900,000?
What if a friend could see the contents when you make your choice but can't communicate with you?

I take Box B.

http://slate.msn.com/?id=2061419
http://members.aol.com/kiekeben/newcomb.html
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iduru

1
Fri 31 Dec, 2004 01:12 am
Schrodinger's cat?

Always go with your first choice.
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val

1
Fri 31 Dec, 2004 03:18 am
Re: Newcombs paradox. What would you do?
Joe, just a question.
How much humans do the test? Only one? Or several?
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Individual

1
Fri 31 Dec, 2004 03:22 am
Neither, I'd pull out a gun and mug him for all he's got.
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val

1
Fri 31 Dec, 2004 05:41 am
Re: Newcombs paradox. What would you do?
JoeFX

Assuming that the entity can predict what I will choose, then I will choose the B box. It doesn't matter when the entity put (or not) the money in the box, because when he did it he already knew what my choice would be. So he did put the money in that B box because he knew I would choose that box.
And I would choose again the B box, no matter how much money is in the A box and no matter what a friend saw inside the B box.
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Pantalones

1
Fri 31 Dec, 2004 02:17 pm
val, that's my reasoning too.
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binnyboy

1
Fri 31 Dec, 2004 11:52 pm
yep
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joefromchicago

1
Sun 2 Jan, 2005 10:39 am
Re: Newcombs paradox. What would you do?
val wrote:
JoeFX

Assuming that the entity can predict what I will choose, then I will choose the B box. It doesn't matter when the entity put (or not) the money in the box, because when he did it he already knew what my choice would be. So he did put the money in that B box because he knew I would choose that box.
And I would choose again the B box, no matter how much money is in the A box and no matter what a friend saw inside the B box.

Although it may have a very good record of predicting, the predictor in no way causes the choice. At most, it anticipates choices accurately. But the only way that we know the predictor is accurate is by reviewing its past record of predictions. We also know, however, that induction can give us no guarantee of future events. There is, therefore, no guarantee that the predictor, howsoever accurate it has been in the past, will be accurate this time.

The logical approach, therefore, is to take both boxes. Since the money is there (or not there) regardless of the choice, it matters not whether the predictor has accurately anticipated our action.
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