I interpret your post as meaning how do we co-exist? How it’s done is another thing, but by reaching agreement would be the way so far.

Not an easy thing to do. At first I thought smaller communities would make this easier, but I don’t think it’s ever been easy.

Harmony: maybe it’s just an ideal. I think the reality is a pragmatic agreement that promises some degree of security for both sides. The idea of security could be many things. If you think about what you want personally and think about what’s stopping you it’s likely to be other people. They want the same thing. So that understanding is pretty important. Then it comes down to compromise. But the other party has to be on the same wave length.

History suggests that sometimes you may have to pick up the sword.

Great leadership might be the way.

One populations victory may be the disharmony of another; war is a means to cause chaos in exchange for harmony.

There is harmony in war, it's just very in-depth.

There tends to be harmony in animal communities who do not, what you suggest, compete but rather try to be ordinated.

Yes, it is co-existing; I had gathered it's about harmony, but after what you said, I'll say it's both harmony and chaos, adding, it's also how you handle chaos.

However, bundled with this is that great harmony can come after chaos.

We are chaos harmonic, and we have controlled natural chaos somewhat so it's conscious.

You don't misunderstand 7 billion people, you can live with the imagination of an entire universes scale.

Keep in mind that in music, harmony refers to things that are different from each other--different pitches--occurring simultaneously.

Especially colloquially, people often use "harmony" so that is has a connotation of "consonance" (rather than "dissonance"), but there's no such connotation in music theory, and consonance versus dissonance are relative/subjective.