of course by the time we had the ability to do von Neumann Probes our anthropomorphic assumption of time scales may have changed.
How much would human life span need to increase for a von Neumann Probe to seem reasonable. I would think a life span of 600 and you're thinking, sure I won't get to see it through, but my allotted genetic offspring that I am allowed at age 500 if either of my other two have failed might.
If you expect to live past a few hundred years it isn't clear why your lifespan wouldn't be indefinite. The prerequisites for achieving the former appear to be more or less the same as those of the latter.
>it isn't clear why your lifespan wouldn't be indefinite.
it also isn't clear why it would be, when achieving something not achieved before you end up uncovering undiscovered problems, opportunities, and constraints.
The point is that reliably making it to a few hundred years requires (AFAICT) full understanding and control over all the elementary biological processes. If you already understand and are capable of freely manipulating every primitive in the system it isn't clear what's left to break.
To put this in mechanical terms, once I know how to replace every last component in my car and have the ability to fabricate new parts for the body and frame under what conditions could my car ever be unrepairable?
and my point still remains, once I know how to do something that has never been done is there a chance that some new factor will be revealed by this ability which will somehow constrain my ability to achieve my true goals? As the description of the scenario was of course fictional I decided to describe it as though some constraint unfamiliar to us now still kept things from going onward.
One particular constraint you can imagine in this fictional situation is that psychologically people who live more than 3 centuries start to have a deep burnout of existence, because there no longer seems to be any challenge or newness, causing them to experience extreme depression and psychological illness of various sorts that most people do not experience nowadays with our short lifespans. Thus there are psychological profiles done, if you are around 500 and you are not shown to have hit the psychological end point of your existence you can be allowed one more child, also dependent on how many children you have had before. This however will be your last child, because no rebuilt human has ever managed to escape "age psychosis" after 600 years of age.
Right. We have no idea how another species perceives time. This could be nothing to them.
And even if they do perceive it like us, that hasn't stopped humans from great projects. How many generations did it take to complete Stonehenge or the Great Wall of China? We're still on top of Voyager too after 50 years.
It would take ~5 million years (in the sender's frame of reference) for a probe to make the journey to Andromeda and then send another back with any information. What would the point of that be?
I read an interesting book called Count to a Trillion.
Astronomers detected an antimatter star a mere 50 light–years from Earth, and the US launched an unmanned mission to go there and learn what it could. Luckily the probe was programmed to transmit its findings multiple times, because the first few transmissions were missed; terrorists had launched a bioweapon that nearly caused an extinction event. Eventually Europe recovered enough to be paying attention. Appended like a footnote to the end of the probe’s transmission of everything it found were pictures of the writing covering the surface of the only moon of the only planet in the system, a gas giant.
The Europeans launched a manned mission a few decades later. One token American, the inventor of the suspended animation technique the crew would be using, was invited along. They went, they learned quite a lot from the Monument, they harvested a quite a lot of antimatter, and then they returned.
What they could decode from the Monument was mostly mathematics. A large portion of it was proofs for various theorems of [cliometrics](https://en.wikipedia.org/wiki/Cliometrics), or quantitative history. With a proper understanding of the mathematics, anyone can predict and even control the evolution of any complex system. It could be a computer program, a network, an organism, an ecology, a society, or all of the above at once. The other interesting bit of math was a complete proof of a system for calculating the value of a trade, given the distance between the participants and their relative level of technology and intelligence. It proves that profitable trade is possible between distant star systems, provided both sides know enough. Proper use of the system allows both sides to know the profit of any trade in advance, meaning no prior coordination need be required. Any two parties can use it to launch trade missions that take millennia to arrive knowing that the other side will already have made the same calculations and be expecting the mission.
The rest of what they decode is astronomy and history. The Monument records that a group of aliens in the dwarf galaxy M3 claim ownership and responsibility for the whole galaxy. Through several layers of delegation they are organizing the creation of life here in the Milky Way. In particular, any and all life arising near the antimatter star was seeded by an intelligence inhabiting a globular cluster 1000 light–years away. Therefore humans owe that intelligence a huge debt and must repay it, effectively making everyone on Earth a slave. As soon as they detect anyone tampering with the antimatter star they are instructed to send a mission to deracinate the planet, carry away whatever life they find, and use it to colonize other star systems. This mission cannot not be sent quickly, as we’re expected to be quite primitive and thus not worth spending very much on, but it will arrive in ~11,000 years whether anyone likes it or not. The crew of the ship then depart for Earth.
When they got back to Earth they found that the whole world was strange. Hundreds of years have past, all the countries are different, and their homes are gone. They end up using some of the antimatter as weapons, defeating the militaries of the world and declaring themselves ruler of all. Between their military power, their knowledge of cliometrics (primitive though it is at this point), and the vast riches of the antimatter that they brought with them, they manage to live in some style.
The main character (the token American from before) and his fiance discover one additional proof of importance: any form of life can be elevated above their boss if they can prove themselves more capable of long–term thinking. All you have to do is engage in really long–term trade. They decide that they should make Humanity equal to their boss’s boss’s boss’s boss, the intelligence at the dwarf galaxy M3, by sending a mission there and back. It’ll take 77,000 years but as long as Humanity survives that long and doesn’t forget about them then Humanity will be vindicated and will no longer be enslaved to anyone. They plan to depart the day after their wedding. They spend the night after their wedding in a disused hotel thousands of miles above the Pacific ocean in the middle of a space elevator.
Alas, that night the main character’s rival calls him out for a duel. He agrees and meets the guy at the base of the elevator. But the duel is a trap; his rival cheats and the space elevator is severed. He is buried under the rubble, wounded but alive, as his wife makes her way up to the ship. She can’t turn the ship around and come back for him and so must continue the mission without him. He decides that one night with his wife is not enough and has to find a way to live on Earth for the next 77,000 years or so until she gets back. Cue sequels.
So there you go. Love seems like a pretty good answer to me, but technically any sufficiently long–term motivation would suffice. I’m sure that you could imagine some, if you put your mind to it.
I was never convinced by cliometrics (including the Asimov version in Foundation). Yes, there are patterns and structural forces, but history is too subject to chaos (in the mathematical sense) for any precise long range predictions.
That's probably true (although not proven!), but every science fiction story is allowed to ask the reader to suspend disbelief when it breaks one law of physics. (At least according to Campbell.) Since the story has no FTL travel or communications it can use that forbearance somewhere else.
How much would human life span need to increase for a von Neumann Probe to seem reasonable. I would think a life span of 600 and you're thinking, sure I won't get to see it through, but my allotted genetic offspring that I am allowed at age 500 if either of my other two have failed might.