Simply discounting self-bias in valuing a life doesn't give you a correct value. The opposite of self-biased is not unbiased.
I'm not sure it's even meaningful to put a dollar value on your own life. And, yes, we'd want to correct for the biases of hating the person in question, as well, which might lead you to undervalue him.
Human skills can be a positive resource. What ever skill are generated during a war, it does not take a war to generate those skills. Those skills could be developed in the absence of war. That those skills are not developed in the absence of war is not an argument I find persuasive that war has provided the benefit of the development of those skills.
I'm not claiming that war is the optimal outcome, only that it could be positive-sum. There may be other choices with an even larger sum. However, maybe the only way to exploit country Y's resources is with war; suppose all diplomatic attempts seem doomed to failure. Then, if the resources are valuable enough, war might be the best option (though we should also take into account how easy it is to underestimate the cost of war).
I don't consider that responses that people make to mitigate adverse circumstances can ever completely negate the adverse consequence. I think the idea that people have that a “silver lining” can completely mitigate an adverse event is part of the zero-sum bias the OP was talking about.
No, the zero-sum bias consists of erroneously thinking that an adverse event is always mitigated by a silver lining. Adverse events are sometimes mitigated by a silver lining. For instance, if you would freely choose to get a papercut for $10, and someone gives you a papercut accidentally, couldn't they mitigate the adverse event by giving you $10?
This is the first part of a mini-sequence of posts on zero-sum bias and the role that it plays in our world today.
One of the most pernicious of all human biases is zero-sum bias. A situation involving a collection of entities is zero-sum if one entity's gain is another's loss, whereas a situation is positive-sum if the entities involved can each achieve the best possible outcome by cooperating with one another. Zero-sum bias is the tendency to systematically assume that positive-sum situations are zero-sum situations. This bias is arguably the major obstacle to a Pareto-efficient society. As such, it's very important that we work to overcome this bias (both in ourselves and in broader society).
Here I'll place this bias in context and speculate on its origin.
Where this bias comes from
It's always a little risky to engage in speculation about human evolution. We know so little about our ancestral environment that our mental images of it might be totally wrong. Nevertheless, the predictions of evolutionary speculation sometimes agree with empirical results, so it's not to be dismissed entirely. Also, the human mind has an easier time comprehending and remembering information when the information is embedded in a narrative, so that speculative stories can play a useful cognitive role even when wrong.
Anatomically modern humans appear to have emerged 200,000 years ago. In the context of human history, economic growth is a relatively recent discovery, only beginning in earnest several thousand years ago. The idea that it was possible to create wealth was probably foreign to our ancestors. In The Bottom Billion, former director of Development Research at the World bank speculates on the motivation of rebels in the poorest and slowest growing countries in the world who start civil wars (despite the fact that there's a high chance of being killed as a rebel and the fact that civil wars are usually damaging to the countries involved)
Neither the developed world nor the countries that Collier has in mind are genuinely good proxies to our ancestral environment, but like the people in the countries that Collier has in mind, our ancestors lived in contexts in which growth of resources was not happening. In such a context, the way that people acquire more resources for themselves is by taking other people's resources away. The ancient humans who survived and reproduced most successfully were those who had an intuitive sense that one entity's gain of resources can only come at the price of another entity's loss of resources. Iterate this story over thousands of generations of humans and you get modern humans with genetic disposition toward zero-sum thinking. This is where we come from.
For nearly all modern humans, the utility of zero-sum bias has lapsed. We now have very abundant evidence that the pie can grow bigger and that win-win opportunities abound. Both as individuals and as representatives of groups, modern humans have a tendency to fight over existing resources when they could be doing just as well or better by creating new resources that benefit others. Modern humans have an unprecedented opportunity to create a world of lasting prosperity. We should do our best to make the most of this opportunity by overcoming zero-sum bias.