(I am aware you didn't invent that saying (I don't know who did), but you used it without thinking about how stupid of a saying it actually is.)
> and yet our brains aren't that far removed from our ape ancestors.
OK, that's just so ridiculous as to verge on absurd. Our brains are so far removed from an ape that you wouldn't know we were related if all you could observe were actions (rather than form and shape).
> are not well-suited for considering really-long-term abstract uncertain problems that require altruism to solve (e.g. the environment as the tragedy of the commons
Any yet somehow we have solved that over and over. And humans are the most altruistic of all the species - witness how we rush to help when there is a disaster, or how much charity we give - or that we invented of concept of charity in the first place!
> or solid agreements between nations to dismantle nuclear arms).
We haven't done that because we don't want to do that, not because we can't. And we don't want to for very good, thought out reasons, not because of some brain lack. You might disagree on the reasons themself, but you can't claim there were no reasons.
> Overcoming that bias, to see humanity in its current state as basically a selfish tribalistic society, is challenging.
And presumably you have done so? And you have one of these flawed brains? You seem to have a contradiction here. Not that I agree with your analysis anyway. You are trying to use tribalistic as a negative but it doesn't have that meaning. And we are not selfish, we are competitive. Selfish would imply hurting others for no gain of your own and while some individuals do that, as a whole we don't.
> that generally we devalue human lives with increasing distance from our own birthplace, country, class, time, etc.
We don't devalue them because they are far, but rather we don't believe we have the ability to do anything about their lives, so we ignore them. The closer someone is to you the more likely you are to help - is that your point? But people don't help more because they are more similar - people help more because they have more ability to do so.