Re: Time Machines, FTL, and P=NP

Michael Ash wrote:
> James Burns <burns.87@[EMAIL PROTECTED]
> wrote:
>

>>Consider, too, that the lady at the bar may have a time machine
>>as well, and hers is guaranteeing that she will only be approached
>>by knights in shining armor (by /her/ definition). Decades later,
>>you are still her knight in shining armor -- by your choice
>>(to all appearance), just as it was her choice to go home with
>>you that night (to all appearance).
>>
>>I guess that's not necessarily a bad thing, but I miss my
>>free will.
> 
> You still have your free will (you can shut off the machine at
> any time, and when other people have machines you're just
> reacting to what they do, even if it's repeated a lot), you just
> don't have any memories of a lot of it.

Actually, I do think that my free will would go away in
certain causality-violating circumstances. But we may not be
in disagreement (about this point) because we may not be agreeing
about what free will is, etc.

If the most effective way I have to affect your behavior
involves persuading you, or bribing you, or threatening you,
or otherwise treating you as though you have a mind with
wants, desires, fears, and so on, then I say that is the
test of whether you have free will. If some other strategy
works better, like changing the settings on your operating
system, then I say you do not have free will.

Suppose I am in a room with a little radio-controlled car
that keeps banging into my right foot. My first thought is
that someone is controlling the car and having fun at my
expense. I would say at that point that car-plus-handler
has free will, although I could be wrong.

Perhaps I would try
appealing to the invisible handler's better nature. Maybe,
after a long enough time, I would threaten them with
the police. These are all strategies that assume you're
interacting with someone or something with a free will.

If it turns out
that there is a magnet stuck to the sole of my shoe and
that, once the magnet is removed, the car stops banging
into me, then I would say the car does not have free will
-- because I no longer think of the car (without
handler) as persuadable, or threatenable, or anything
else along those lines.

If I use a causal loop to get a woman to come home with
me, then I am not persuading her in any important sense.
I may speak some words or I may not; the critical step
is that I am paging through futures until I find one
to my liking. The procedure doesn't actually need me
to think about her wants, needs, principles, etc at all,
and so I would say that she has no free will in the matter,
no more than the little car "chooses" to stop banging
into me when I peel the magnet off of  my sole.

I imagine that the woman would feel no different that
night than she would before or after. She'd probably
be offended to be told she didn't have free will in the matter.
My point, though, is that free will is not something
that she or you or I have internally, like a skill or a memory.
My definition of free will is that it is whatever I think
you (or she) have when I think you can be persuaded.

Because the lady at the bar will be going home with
me (I know this because I peeked ahead), I know that
I do not have to persuade her to come. In fact, I know that
it would be impossible to persuade her to do otherwise,
no matter how much she feels like she has free will.

(Let me clarify one point: She will still have free will
with regard to everything except going home with me.
Compare her situation to that of a man in a barrel going
over Niagra Falls. He has free will, too, about everything
except about where he and his barrel are going.)

[...]
> I think there are two different arguments which can be made here,
> along the lines of the weak and strong anthropic principle.
> 
> The "strong" version would be, this wacky crap is nonsensical,
> therefore causality is required.
> 
> The "weak" version would be, this wacky crap is nonsensical,
> we can't even discuss it properly, so there's no point in
> discussing what happens because we just can't know.
> 
> I agree with you that the "strong" version is kind of a bad way
> to do things, but I think the "weak" version has some merit.
> The ideas I've come up with just scratch the surface. Trying to
> think about the ultimate consequences of causality violation is
> like Ben Franklin trying to derive the Internet from the results
> of his kite/lightning experiment. It's interesting to discuss
> but we shouldn't think that these ideas would necessarily bear
> out in reality.

I'm glad you think the strong version of "wacky crap means no time
machine" is a bad argument. That's actually the one I've seen in
such discussions more often than not.

I guess I don't understand your "weak" argument. Discussions
always start out crude, ill-informed, badly phrased. The
hope is always that they will become clearer, more useful
discussions, but, of course, that can't happen if the
earlier silly discussions don't happen.

And I don't think I've ever heard "we just can't know"
without it being closely followed by "well, how could
we find out?"

I agree with your estimate of how far along
we are in understanding causality, except that I think
comparing us to Ben Franklin is much too generous.

My own bet is that the only "application" we will ever
have is an understanding of why time machines are
impossible, but that is something I would like
to see.

Jim Burns