I LOVE “Historical-Long Generation” – I have been using the concept (though I’ve always called it the “Centennial Generation”) my entire adult life – for exactly the reasons Greg gives.

I very much view Historical-Long Generation (HLG) as the temporal analog of “Degrees of Separation” (DOS) – a.k.a. the “Six Handshakes Rule” – and both have profound implications not only for everyday conscious awareness and spirituality [if that’s what you’re striving for], but for allometry, fractals, topology … and other mathematical fields/applications. Also physics, politics … ecology … systems theory. The list is darn near infinite. Collectively,, they come pretty damn close to being a Theory of Everything.

Too few people reflect, often enough, upon the implications of HLG/DOS, which I’ll confess have profoundly affected my own world view. And just for the record – though of course I have no idea whether you folks out there can claim any shorter connections – when you “shake MY hand,” you are only TWO or THREE degrees of separation from every US president from FDR through Trump. Ditto Joseph Stalin, Chairman Mao. Chiang Kai-shek, … and innumerable other famous/infamous world leaders/musicians.

As for scientists – too many to mention – again, meeting me you’d be only 2-3 DOS at most. And I am not especially remarkable, nor accomplished; I have not travelled a great deal, or been to all that many places/events. (Though I did meet Margaret Mead as a child. I mean, I (not she) was the child.)

Okay, ’nuff said. The implications of HLG/DOS are mind-blowing (or maybe I just have an easily-blown mind).

What’s actually more interesting to me are the network-theory implications as applied to the Western vs non-Western worlds. Or, for that matter, to “celebrities” in any domain (sports, politics, science, entertainment) vs “ordinary” people. For example, HLG/DOS increases ~ 1-2 when applied to people in far-away places and/or different societies. In other words, then one must think in terms of local networks and their relationships to the larger ones and the world (or any “system”) as a whole.

In human beings the biological era does now not have a popular length but there are limits. Going the other manner your youngsters and their generation are the primary descending era.