Szydagis' point 3: Interstellar travel is too hard

[jdog]

It is arguable, and quite rationally so, that a copy of you cannot contain 'your' consciousness, especially if you already exist when the copy is created and thus already possess 'your' consciousness. And to me this is the whole issue with Star Trek type transporters, immortality via uploading to a computer, etc, etc...or with the idea of cloning copies such as in the Altered Carbon series or in the game Eve Online.

I think all those alleged future technologies are defying some pretty basic laws of physics. Why would a copy of me be the actual me...any more than the next door neighbour's identical car ( that rolled off the production line at the same time ) could be my car.

Of course, there is a sort of counter-argument in the form of a 'Ship of Theseus' bit by bit replacement, but I think with enough analysis even that fails. We won't be quantum entangling our consciousness to clones on Beta Reticuli....not only not any time soon...but ever.

Well, with that attitude, no clone is going to want to be entangling with your consciousness anyway!

 

[Gary C]

Since I'm spitballing in this thread WRT fermi paradoxe I believe its been shown that once some species achieves a van neumann ability (provided we dont kill ourselves we will achieve in the next millennium) then they (the machines) can visit all the planets in a galaxy within a few million years, thus why hasn't it happened?

This is an updated version of my reply from an earlier thread. The Fermi Paradox comes up eventually on every astronomy and space forum and social media site I visit so I now keep a canned response on file.

Hope this helps.

 

[jdog]

Yes...it also violates the law of conservation of energy. Probably THE biggest law that can be violated.

Let's say I have a time machine and 'go back in time'. Well, that causes mass/energy to disappear from now....which itself violates the law....and to re-appear in the past...which again violates the law. I mean, my time machine just appearing out of nowhere is effectively the creation of new mass/energy from nothing, in the past. And it gets worse...as the atoms my time machine is made of would actually already exist back then, so I'd be violating various quantum laws regarding quantum states and cloning.

That's what all backward time travel plots forget. Whatever you are taking back in time already exists ( in some form ) back then. You are thus creating the grievous scientific crime of duplicating atoms in the past.

There was some vintage sci-fi novel, by Moorcock or someone of his era, musing on the difficulties of time travel and envisioning it as trying to move all your molecules against a river of all the other instances of your molecules in those post iterations. At best you're converting yourself into the same configuration of yourself at a past state; there would be no future "you" consciousness to be aware of the past; worst case you dissolve, possibly turning back into all the nutrients you've ever digested.

 

[Scaramanga]

This is an updated version of my reply from an earlier thread. The Fermi Paradox comes up eventually on every astronomy and space forum and social media site I visit so I now keep a canned response on file.

Hope this helps.

There's no Fermi paradox if there's nobody else out there....at least within any detectable range.

People have this bizarre idea that there 'must' be other life out there because there's so many planets. But that is bad science and bad statistics. One cannot possibly argue a 'must' based on a large number...when the odds against life forming may be an even larger number.

Simply being impressed with the number of planets is a fallacy. We have a sample of one. We simply do not know if it is 1 in a million or 1 in 10^527, and there is nothing that guarantees that the odds against life are smaller than the number of planets.

 

[Scaramanga]

There was some vintage sci-fi novel, by Moorcock or someone of his era, musing on the difficulties of time travel and envisioning it as trying to move all your molecules against a river of all the other instances of your molecules in those post iterations. At best you're converting yourself into the same configuration of yourself at a past state; there would be no future "you" consciousness to be aware of the past; worst case you dissolve, possibly turning back into all the nutrients you've ever digested.

Well, I could get in my time machine that I created yesterday and go back to yesterday and pick up myself and bring past me to today. Then we could both go back and meet the two of me from yesterday and bring them to today. And pretty soon I could exponentially, in powers of 2, create more 'me' than there are atoms in the entire universe. If that's not proof that time travel to the past is impossible then I don't know what is.

 

[Mendel]

Why would a copy of me be the actual me...

you'd be indistinguishable except for your history
nobody could prove you're not you

that's why cars carry serial numbers

 

[Mendel]

Well, I could get in my time machine that I created yesterday and go back to yesterday and pick up myself and bring past me to today. Then we could both go back

no, you couldn't

if you change spacetime such that you don't exist from Monday to Tuesday, then there is no "you" on Tuesday that existed through this time. The result of this time travel is one "you" on Tuesday either way, you can only change how it gets there.

 

[Mendel]

Yes...it also violates the law of conservation of energy. Probably THE biggest law that can be violated.

Let's say I have a time machine and 'go back in time'. Well, that causes mass/energy to disappear from now....which itself violates the law....and to re-appear in the past...which again violates the law.

That's teleportation.

I expect that reversing the flow of time directly violates the second and third laws of thermodynamics (about entropy increasing).

 

[Eburacum]

If the universe allowed time travel, I'd expect a flood of refugees coming back from the Heat Death of the Universe to live in our more comfortable environment; this would happen exponentially (and instantly), causing the universe to collapse in a Big Crunch due to the excess (unconserved) mass. This hasn't happened, so time travel is likely impossible.

 

[Todd Feinman]

If the universe allowed time travel, I'd expect a flood of refugees coming back from the Heat Death of the Universe to live in our more comfortable environment; this would happen exponentially (and instantly), causing the universe to collapse in a Big Crunch due to the excess (unconserved) mass. This hasn't happened, so time travel is likely impossible.

Would you be going back to the same universe if time travel were possible? Or an alternate? At least with the block conception of the universe, it would be an alternate, I think.

 

[JMartJr]

if you change spacetime such that you don't exist from Monday to Tuesday, then there is no "you" on Tuesday that existed through this time. The result of this time travel is one "you" on Tuesday either way, you can only change how it gets there.

Unless time travel does not work that way. Either paradoxes (at least as viewed without time travel) are integral to the fun of time travel stories, and since time travel is, so far, totally fictional, I'd rule that time travel paradoxes are definitely allowed.

Spoiler -- if you have not read "Flight of the Horse" and other tails of Hanville Svetz, reluctant time traveller, but might someday, skip this:

Spoiler: illustrative plot point from Svetz's stories which gives away too much

In the stories, Svetz and his associates travel back in time from a post-semiapocalyptic future to a past from which only fragmentary records survive, in search of interesting animals that went extinct when humans wrecked the environment. What they don't know is that, since time travel was always considered fictional, when they go back past the date of the invention of the machine, they slide across timelines into fictional universes. So Svetz is surprised when the horse he went to capture almost kills him with it's spiral horn, and he suffers major burns when the gila monster lizard, which is MUCH bigger than expected, breaths fire all over him while flapping it's vestigial bat wings...

Would you be going back to the same universe if time travel were possible? Or an alternate? At least with the block conception of the universe, it would be an alternate, I think.

More worrisome, would you come BACK to the right universe? Svetz's machine gets around that by having the massive machinery of the time machine stay firmly in his present, in the Institute for Temporal Research, while just poking the "extension cage" back into time. It is said that the viewof the side of the cage that extends back through time to the rest of the machinery is disconcerting... but at least when you go home, you are reeled back in to where you started.