Question

how did it prove that global solidarity possible?

Answer 1

In the very long term, possible. We are talking about evolutionary time scales though.Consider that up to about say, 5000 years ago, the blink of an eye, the largest cohesive human societies were small, tribal, and largely limited by Dunbar’s number. A larger society is more resilient and less likely to fall, so it supports its member’s survival better and the advantages lead to social evolution that build larger societies and nations.