Re: Time Machines, FTL, and P=NP

On Feb 20, 11:50 am, James Burns <burns...@[EMAIL PROTECTED]
> wrote:
> Michael Ash wrote:
> > Crown-Horned Snorkack <chornedsnork...@[EMAIL PROTECTED]
> wrote:
> >>But how would you write programs where you have oracle function at
> >>your disposal?
>
> > First, a warning, I haven't thought this through too thoroughly.
>
> I can't claim to have thought it through thoroughly, but I have
> chewed on this particular bone for a number of years. For what
> it's worth, your analysis closely matches mine.
>
> > Having some more fun, imagine picking up women in a bar. Give the
machine
> > a list of women, and a database of pick-up lines. It feeds you one,
and
> > you report back how well it worked. This will look like the machine
> > automatically points you to a woman and gives you a pick-up line which
> > will sweep her off her feet.
>
> Now that's a twist I hadn't considered.
>
> 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.
>
> It seems to me that someone who puts themselves in a causal
> loop this way is opening up the casing on the engine that runs
> the universe and sticking their fingers in it to see how it works.
> We could have the makings of a prize-winning video here.
>
> > Anyway, this is why scientists tend to assume that causality isn't
> > violated in the universe, because if it is, all kinds of wacky crap
> > happens.
>
> I don't really believe in the possibility of time machines, but
> I have a sense that they have not yet been ruled out, and it seems
> as though we ought to be able to do that.
>
> The interesting thing about the "wacky crap happens"
> argument against causality violation is that it would have
> worked just as well as an argument against life arising
> in the billions of years between the big bang and the first
> occurrence of life. Compared to the boring things that
> suns and planets and rocks and clouds of gas do, it's
> no stretch at all to call wacky: locally decreasing entropy,
> natural selection, photosynthesis, predator-prey relationships,
> and the internet. And that's not even including celebrities.
>
> Would the first causality violation be followed by
> scads of activities that have never been seen before
> in the history of the universe. Absolutely. Does that mean
> there will be no first causality violation? I don't
> see how that step in the argument is supposed to go.
>
> Jim Burns

You know, we can already build universes where time travel is possible
(and in the not-too-distant future, populate them with thinking
beings)  I don't think that causality violations may turn out to be
all that bad in the end.