Thanks, Jonah. I think skepticism about the dominance of the far future is actually quite compelling, such that I'm not certain that focusing on the far future dominates (though I think it's likely that it does on balance, but much less than I naively thought).

The strongest argument is just that believing we are in a position to influence astronomical numbers of minds runs contrary to Copernican intuitions that we should be typical observers. Isn't it a massive coincidence that we happen to be among a small group of creatures that can most powerfully affect our future light cone? Robin Hanson's resolution of Pascal's mugging relied on this idea.

The simulation-argument proposal is one specific way to hash out this Copernican intuition. The sim arg is quite robust and doesn't depend on the self-sampling assumption the way the doomsday argument does. We have reasonable a priori reasons for thinking there should be lots of sims -- not quite as strong as the arguments for thinking we should be able to influence the far future, but not vastly weaker.

Let's look at some sample numbers. We'll work in units of "number of humans alive in 2014," so that the current population of Earth is 1. Let's say the far future contains N humans (or human-ish sentient creatures), and a fraction f of those are sims that think they're on Earth around 2014. The sim arg suggests that Nf >> 1, i.e., we're probably in one of those sims. The probability we're not in such a sim is 1/(Nf+1), which we can approximate as 1/(Nf). Now, maybe future people have a higher intensity of experience i relative to that of present-day people. Also, it's much easier to affect the near future than the far future, so let e represent the amount of extra "entropy" that our actions face if they target the far future. For example, e = 10^-6 says there's a factor-of-a-million discount for how likely our actions are to actually make the difference we intend for the far future vs. if we had acted to affect the near term. This entropy can come from uncertainty about what the far future will look like, failures of goal preservation, or intrusion of black swans.

Now let's consider two cases -- one assuming no correlations among actors (CDT) and one assuming full correlations (TDT-ish).

CDT case:

• If we help in the short run, we can affect something like 1 people (where "1" means "7 billion").
• If we help in the long run, if we're not in a sim, we can affect N people, with an i experience-intensity multiple, with a factor of e for uncertainty/entropy in our efforts. But the probability we're not in a sim is 1/(Nf), so the overall expected value is 1/(Nf)Nie = ie/f.

It's not obvious that ie/f > 1. For instance, if f = 10^-4, i = 10^2, and e = 10^-6, this would equal 1. Hence it wouldn't be clear that targeting the far future is better than targeting the near term.

TDT-ish case:

• There are Nf+1 copies of people (who think they're) on Earth in 2014, so if we help in the short run, we help all of those Nf+1 people because our actions are mirrored across our copies. Since Nf >> 1, we can approximate this as Nf.
• If we help by taking far-future-targeting actions, even if we're in a sim, our actions can timelessly affect what happens in the basement, so we can have an impact regardless of whether we're in a sim or not. The future contains N people with i intensity factor, and there's e entropy on actions that try to do far-future stuff relative to short-term stuff. The expected value is Nie.

The ratio of long-term helping to short-term helping is Nie/(Nf) = ie/f, exactly the same as before. Hence, the uncertainty about whether the near- or far-future dominates persists.

I've tried these calculations with a few other tweaks, and something close to ie/f continues to pop out.

Now, this point is again of the "one relatively strong argument" variety, so I'm not claiming this particular elaboration is definitive. But it illustrates the types of ways that far-future-dominance arguments could be neglecting certain factors.

Note also that even if you think ie/f >> 1, it's still less than the 10^30 or whatever factor a naive far-future-dominance perspective might assume. Also, to be clear, I'm ignoring flow-through effects of short-term helping on the far future and just talking about the intrinsic value of the direct targets of our actions.