Re: Time Machines, FTL, and P=NP

Michael Ash wrote:
> Crown-Horned Snorkack <chornedsnorkack@[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