Re: Time Machines, FTL, and P=NP

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

That's good to hear.

>> 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.

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.

>> 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.

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.

-- 
Michael Ash
Rogue Amoeba Software