Think of Petrov: http://lesswrong.com/lw/8f0/existential_risk/
We effectively credit him with saving the world. If it weren't for him, most of us might not be around. I consider him a hero. From a moral perspective I would rather be him than Bill Gates, who has greatly reduced suffering and disease in the modern world. Just because of the impact on the future.
I don't see how this is a shortcoming.
If I am leading a company, I cannot know for sure that a certain action will have a certain outcome – or that any action taking will actually be the cause of a given outcome. That's not going to prevent me from doing my best to build a good product and make a profit.
In the same way, the uncertainty inherent in reducing existential risk shouldn't prevent us from doing our best to reduce it.
For example, consider how many people died mining coal in the past couple of centuries, or how many natives died when colonizing forces spread them diseases or outright committed genocide.
Sure, it's awful, but would the world really be a better place if America were limited to some traders on the East coast? Or if England had never really gotten the Industrial Revolution thing figured out?
We can't really reason in human terms when talking about the species writ large.
So, as usual, the whole debate will be solved with brute force and whoever wins will get the right to speak like you.
Are there really people thinking the Native American Genocide was somehow worth it? That's despicable. Tell me because I'm not sure, you classify the genocide as "transient effect" or "meaningful policy"?
> [...] would the world really be a better place if America were limited to some traders on the East coast?
Irak war anyone? That's how USA makes world a better place.
(1) is problematic because: a) it's not true at the scales we're talking about; and b) it's intrinsically tied to how someone existing in the present values future benefits. It takes a very narrow view of "utility" to argue that only the value to those in the present is relevant.
(2) is problematic because the assumption isn't necessarily true. Imagine a world where there are no investments that yield a consistent return such that an investment at time T0 yields exponentially increasing wealth at time T0+T. In such a world the second principle provides no reason to engage in temporal discounting. At the scales we're talking about, this second principle starts to break down. You can't assume that an investment in the present will continue to yield returns indefinitely into the future if your actions result in their being no future humans.
I think a more apropos basis for a guiding principle in this area is the observation that, in absolute terms, the productivity of society grows exponentially. A single person 1,000 years from now will produce much more, in absolute terms, than a single person today. If we define our metric more objectively, something as the sum of all production over the existence of humanity, then the proper course of action is the one that preserves as many future lives as possible, even at the expense of present lives, because most production will happen in the future.
Still, 100 years is often considered a reasonable limit on such things as 5% * 100 years = 0.6%.
23% of all goods and services made since 1AD were made between 2001 and 2010: http://www.economist.com/node/21522912
If a similar pattern holds true, then the opportunity cost, in absolute terms, of a decision that results in fewer future humans is absolutely staggering.
It's odd to give that much moral weight to the potential future existence of unborn people centuries from now; how does that not favor simply having as many babies as possible?
But on a purely biological note, natural selection favors just that: those who make more babies than anyone else, who then go on to make more babies than any of their contemporaries, etc etc etc.
It's really an interesting moral discussion - it's like an extension of the "sacrifice one person to save five" classical dilemma, but I really can't agree with his flippant assertion that our moral obligation to the unborn future billions eclipses that to our obligation to help our contemporaries. And he's not even talking about preserving the planet for the future generations, he's merely concerned with them being born in the first place.
Also, his argument has the same short-coming as the "sacrifice" dilemma: We cannot know for sure that a certain action will have a certain outcome - or that any action taken was actually the cause of the outcome.