Stathis has another good thought experiment.
> You are in a room strapped to an electric chair with a counter counting down
> from one minute. There are two buttons accessible to you on the chair,
> marked A and B. Pressing button A will cause the chair either to release
> you, with Pr=0.4, or immediately electrocute you, with Pr=0.6.
Okay, so we loyal adherents of the MWI understand that in .6 of my measure,
I die instantly, and in .4 of my (constant) measure, I go free. So far,
then, pressing A cuts down on my measure by sixty percent. Not good.
> Pressing button B will cause the chair to immediately release
> you (i.e. with Pr=1),
ah, that's better
> but it will also teleport itself along with a copy of you still strapped to
> the chair to another room, where the countdown will continue.
Oh goody. More runtime. Where do I sign up? (True, there is a little
predicament, but it's not at all serious to me!)
> When the counter reaches zero, you will be electrocuted. Meanwhile, you can
> press the buttons as often as you want.
You are TOO KIND! I see a wonderful panorama of vastly, vastly increased
runtime opening up before me. Already my finger is flexed to press the
button just as fast as I can humanly manage! Surely I can do so several
hundred times in a whole minute.
> The obvious thing to do would seem to be pressing button B - guaranteed
> freedom. However, when you press B, nothing seems to happen:
Ah, what *seems* to happen. Oh! how people are so often deluded by
> you are still strapped to the chair, and the counter continues
> its countdown. [Correction: one instance of me is still strapped
> to the chair but many more instances have already been freed.
> I have brain, and accurate information, and I know this.] On
> closer inspection, it does look as if the room is a little
> different, so you conclude that you have actually been the
> teleported copy. Undeterred, you press the button again, and
> again, and... every time it is just the same:
Yeah, just like the character in my story who was trying to get out
of the pit, sort-of realizing and sort-of not realizing that he both
succeeded *and* failed on each and every press of the button.
It only *seems* to be the same to the instance still in the chair!
> you are still strapped to the chair in a room almost indistinguishable
> from the last one!
> Desperately, you press button B as quickly as you can,
Desperately? Are you kidding? With the greatest joy I can imagine!
Winning the California lottery is nothing compared to this!
> but after over 100 presses it seems clear that however many times
> you press it, you will still end up strapped to the chair.
Yes, but I have a brain. I know that this is only the appearance.
I *know* that in reality I am in many places enjoying much much
more of life than was ever, ever possible before.
> What are you going to do when the counter reaches one second? Will
> you keep pressing B, or will you try button A?
I would never press A. The button A is for people who don't
understand that they're programs, who don't understand that
they can be in two places at the same time. In the last tenth
of a second hopefully I will still get in a button-press or two,
and for each additional button-press I manage to squeeze in,
there will be a new, liberated instance that gets more life for