This sound like an insane ethical framework, though I'm sure the actual writings of longtermists are more nuanced that what is portrayed in the article, I hope.
So utilitarianism’s primary problem - we can’t make a consistent, calculable, useful, and agreeable utility function to aid decision making - is solved by overruling everything with the risk of extinction (consistent, calculable insofar as making a plausible argument that odds of extinction from X are greater than zero, useful that it informs how to proceed wrt X, and arguably agreeable because everyone knows extinction bad)
Anyways my personal POV is that a good utility function should discount future utility, which brings us back to the incalculability issue. But if you treat future utility undiscounted, it makes it very easy to convince yourself of crazy things
Basically, longtermism is willing to sacrifice everything in the present - health, wellbeing, a livable present - in order to save the existence of hypothetical human (or formerly human) beings in a presumed "glorious" future.
Except, no matter which point in time you are, there is always a future - so the moment we arrived in the supposed glorious future, there would be another future to work towards and another population of future humans to sacrifice everything to. In that regard, longtermism would the proverbial donkey chasing the carrot in front of its face.
With the one difference that the donkey is following an incentive, i.e. it discounts the present because the future appears more desirable to it. In contrast, longtermism is presented as a moral obligation: Because the "death by nonexistence" of future humans is seen as equivalent to actual death, you have to prioritize future humans if you don't want to be saddled with an infinite amount of guilt. If the future is seen as more desirable is irrelevant.
Consequently, the "glorious future" can never appear because at that very moment, we'd have to stop sacrificing the present for the future - and thus commiting an atrocity on the future humans.
So my impression is that if you took longtermism seriously, it would really lead to all times being miserable, not just the present.
Longtermism isn’t about acceleration per se, it’s about avoiding extinction
Right now it’s plain to see mankind could see extinction in a few hundred or thousand years, for example a freak meteor. Or we could (maybe) irrevocably set back human civilization with a global thermonuclear war.
Humanity and nature both have some capacity to violently and suddenly end humanity. In theory if we were distributed to the stars, that might[0] not be the case. At such point, the risk of extinction goes to 0, and longtermism should become the same as bog standard utilitarianism, or atleast that’s how I see it
[0] unless we invent weapons to suddenly destroy ourselves on a galactic scale, like antimatter bombs delivered on FTL missiles
Personally, I'm interested in living a good life and for as many other people as possible (who are currently alive or are very likely to be born soon) to be able to do so as well.
I honestly couldn't care less whether Earth in the distant future is populated by lifeforms that share some DNA with me or by other lifeforms that don't.
Or to take the freak meteor you mentioned. Such an event would no doubt be horrible - but more because of the immediate experience of those people who had to endure it, experience nuclear winter, collapse of civilisation, ect. However if the meteor really managed to wipe out all humans then... what? There would be no one left to judge. Earth would go on like it did for billions of years before humans.
On the other hand, why should we endure greatly reduced quality of life (through e.g. increasing effects of climate change) only so we get the economic output required to launch some rocket to mars and plant some DNA there?
So why exactly the focus on the survival of something abstract like "the human race" instead of the lives of the actual humans?
- reliance on apocalyptic fantasies to defend unethical decisions (while actual suffering and real threats flourish)
- inability to comprehend pragmatic humanistic and ethical thinking unless it's justified by irrational utopian fantasies (e.g. space civilization)
It's some kind of a perverse attempt to define agnostic morals.
But sincerely, I don't even believe that - it's more like a modern scam religion to distract from actual problems.
E.g, AI could be used to limit resource consumption, provide efficient public transport, feed the world.
Instead it'll be used to maximize resource consumption of rich people (cough, autonomous self-driving electric cars, but not for everyone...)
This is more or less how I feel. I’m sure some (most?) proponents of longtermism genuinely agree with the philosophy. But then, it’s a time honored tradition of the rich and powerful to soothe their conscience with philosophies that conveniently paint their actions and power as a moral good.
One thing I’ve learned in life is that brilliant folks are more than capable of convincing themselves of what they want to believe, whether or not it sounds compelling to someone outside their bubble.
In other words, Longtermism tells you to give preeminent weight to matters you have no way of knowing the nature of or whether you're improving things or not. At that point, you might as well switch to astrology.