- Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ] [ by messages with attachments ]

From: Wei Dai <weidai.domain.name.hidden>

Date: Fri, 13 Feb 1998 03:21:19 -0800

On Fri, Feb 13, 1998 at 05:55:18PM +1000, Mitchell Porter wrote:

*> 'Quantum suicide' is a ridiculous experiment. Suppose you tried to
*

*> kill yourself ten times and failed. What does that prove about the
*

*> existence of other universes?
*

*>
*

*> Tegmark claims that MWI uniquely predicts that an experimenter
*

*> who attempts quantum suicide will hear ten clicks - but then says
*

*> that in most worlds, the experimenter will be dead before the tenth
*

*> attempt. What this boils down to is the assertion that *if* the
*

*> experimenter survives, they will have heard ten clicks. *All* the
*

*> interpretations agree on that.
*

I think what Tegmark is saying is that conditional expectation of the

experimenter given that MWI is true is that he will hear ten clicks, but

his conditional expectation given that MWI is false is that he will hear

only a few clicks. So if he hears ten clicks he would conclude MWI is

likely to be true.

This type of argument relies on a concept I call sensory probability. That

is, probability of statements of the following form: "I will perceive x."

One could argue that this is the only kind of probability that really

matters. (Or maybe it doesn't matter at all. I'm not sure which.) It is

certainly very paradoxical. Let me give two examples, simpler than the

quantum suicide.

1. An experiment calls for the experimenter to flip a fair coin. A device

is set up so that if it lands heads, the experimenter would be killed

before perceiving this. What probability should he assign to the

statements "I will perceive heads" and "I will perceive tails."

2. An experiment calls for the experimenter to flip a fair coin. A device

is set up so that if it lands heads, the experimenter would be duplicated

(i.e. a copy would be made of his body) and both copies would witness the

result. What probability should he assign to the statements "I will

perceive heads" and "I will perceive tails."

I think Max would say 0, 1, 2/3, 1/3, respectively. I now suspect there

are some serious paradoxes associated with sensory probability, but I need

to think about it some more.

Received on Fri Feb 13 1998 - 03:23:42 PST

Date: Fri, 13 Feb 1998 03:21:19 -0800

On Fri, Feb 13, 1998 at 05:55:18PM +1000, Mitchell Porter wrote:

I think what Tegmark is saying is that conditional expectation of the

experimenter given that MWI is true is that he will hear ten clicks, but

his conditional expectation given that MWI is false is that he will hear

only a few clicks. So if he hears ten clicks he would conclude MWI is

likely to be true.

This type of argument relies on a concept I call sensory probability. That

is, probability of statements of the following form: "I will perceive x."

One could argue that this is the only kind of probability that really

matters. (Or maybe it doesn't matter at all. I'm not sure which.) It is

certainly very paradoxical. Let me give two examples, simpler than the

quantum suicide.

1. An experiment calls for the experimenter to flip a fair coin. A device

is set up so that if it lands heads, the experimenter would be killed

before perceiving this. What probability should he assign to the

statements "I will perceive heads" and "I will perceive tails."

2. An experiment calls for the experimenter to flip a fair coin. A device

is set up so that if it lands heads, the experimenter would be duplicated

(i.e. a copy would be made of his body) and both copies would witness the

result. What probability should he assign to the statements "I will

perceive heads" and "I will perceive tails."

I think Max would say 0, 1, 2/3, 1/3, respectively. I now suspect there

are some serious paradoxes associated with sensory probability, but I need

to think about it some more.

Received on Fri Feb 13 1998 - 03:23:42 PST

*
This archive was generated by hypermail 2.3.0
: Fri Feb 16 2018 - 13:20:06 PST
*