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"Immortality is cool and all, but our universe is going to run down from entropy eventually"
I consider this argument wrong for two reasons. The first is the obvious reason, which is that even if immortality is impossible, it's still better to live for a long time.
The second reason why I think this argument is wrong is because I'm currently convinced that literal physical immortality is possible in our universe. Usually when I say this out loud I get an audible "what" or something to that effect, but I'm not kidding.
It's going to be hard to explain my intuitions for why I think real immortality is possible, so bear with me. First, this is what I'm not saying:
So what am I saying?
A typical model of our life as humans is that we are something like a worm in 4 dimensional space. On one side of the worm there's our birth, and on the other side of the worm is our untimely death. We 'live through' this worm, and that is our life. The length of our life is measured by considering the length of the worm in 4 dimensional space, measured just like a yardstick.
Now just change the perspective a little bit. If we could somehow abandon our current way of living, then maybe we can alter the geometry of this worm so that we are immortal. Consider: a circle has no starting point and no end. If someone could somehow 'live through' a circle, then their life would consist of an eternal loop through experiences, repeating endlessly.
The idea is that we somehow construct a physical manifestation of this immortality circle. I think of it like an actual loop in 4 dimensional space because it's difficult to visualize without an analogy. A superintelligence could perhaps predict what type of actions would be necessary to construct this immortal loop. And once it is constructed, it'll be there forever.
From an outside view in our 3d mind's eye, the construction of this loop would look very strange. It could look like something popping into existence suddenly and getting larger, and then suddenly popping out of existence. I don't really know; that's just the intuition.
What matters is that within this loop someone will be living their life on repeat. True Déjà vu. Each moment they live is in their future, and in their past. There are no new experiences and no novelty, but the superintelligence can construct it so that this part is not unenjoyable. There would be no right answer to the question "how old are you." And in my view, it is perfectly valid to say that this person is truly, actually immortal.
Perhaps someone who valued immortality would want one of these loops to be constructed for themselves. Perhaps for some reason constructing one of these things is impossible in our universe (though I suspect that it's not). There are anthropic reasons that I have considered for why constructing it might not be worth it... but that would be too much to go into for this shortform post.
To close, I currently see no knockdown reasons to believe that this sort of scheme is impossible.
I have a previous high impliciation uncertainty about this (that would be a crux?). " you can't accelerate enough to turn around " seems false to me. The mathematical rotation seems like it ought to exist. The prevoius reasons I thought such a mathematical rotation would be impossible I have signficantly less faith in. If I draw a unit sphere analog in spacetime having a visual observation from the space-time diagram drawn on euclid paper is not sufficient to conclude that the future cone is far from past cone. And thinking that a sphere is ... (read more)