# Re: another puzzzle

```On 6/17/05, Stathis Papaioannou <[EMAIL PROTECTED]> wrote:
>
> You find yourself in a locked room with no windows, and no memory of how you
> got there.
> (...) a light (...) alternates between red and green every 10 minutes.
(...)
> Every 10 minutes, the system alternates between two states. One
> state consists of you alone in your room. The other state consists of 10^100
> exact copies of you, their minds perfectly synchronised with your mind, each
> copy isolated from all the others in a room just like yours.
>
> Your task is to guess which colour of the light corresponds with which state
> and write it down. Then God will send you home.
(...)
> But just as you are about to write down your conclusion, the light changes
> to green...
>
> What's wrong with the reasoning here?```
```
To make the story more visualisable, imagine that God throws a coin
(since he doesn't play dice) to decide whether he will initialise the system
in state A (one person) or B (many). We can imagine that at this point
the universe is split in two, and in universe 1 there are many people
in the room, while in universe 2 there is only one.

After ten minutes, God switches the state of *both* universes. In
universe 1 there is now one person in the room, while in universe 2
there are many, most of which with a false memory of being there
for more than 10 minutes.

This happens for a while before the people in the rooms start to learn
about the experiment and God's game. But you can convince yourself
that it doesn't matter much what was the initial state and how many times
the light has switched; if you believe God's story, the most likely is that
you have just been created after the last switch, and you have a false
memory of being there for a while.

Eric.

```