> Surprisingly, it’s not our shared language or even our ability to dominate other species that defines us but rather, our shared fictions.

I read his book where he talks about this. It makes some sense: you can operate at varied scales if you have shared fictions.

When you meet a complete stranger, you're both members of the human race, sharing a desire for a better future. Meet a fellow countryman, and there are songs and stories that bind you together. Work for the same company and there's internal culture as well as the glorious leader you both work for. Support the same football team and you both remember that night in Istanbul. You were sitting at home in Liverpool, he was in Malaysia.

Hard to tell as with anything historical whether this is the most convincing explanation though. I'm sure there's other things that separate us from the animals? But a compelling enough story and he tells it well.