There are several case histories - the most poignant of which was to story of the Norse settlement at Greenland. The real problem here was that European people had moved to a place that was superficially similar to home, but the soil and other conditions had notable differences.
The Greenland Norse folks saw themselves as Christians, as well as Europeans, and were determined to cling onto that heritage instead of adopting the ways of the native Inuit in response to the situation they were in.
There was a choice before them as to what parts of their heritage to cling to and which to simply abandon. Sadly they clung to the wrong bits, Diamond asserts.
Today, as individuals, and as nations , we face change and uncertainty. how do we see ourselves? what do we consider worth keeping and what do we think we need to let go?
our society has gotten used to thinking in terms of 'we are what we own' . ask someone who they are and they reply with their occupation, most likely. "I'm a teacher" they reply, or some other job is mentioned. No one says "I'm a Methodist", or a Conservative, or an optimist, in answer to the question 'who are you?', it seems.
I think that a lot of things have changed for men in society. "I am a man because..." is harder for this generation to answer. Diamond does not talk about gender identity in the book, but the whole idea of identity and culture as a driving force behind social survival or social collapse is an interesting concept.
In the book, Diamond does stress the adaptability and ingenuity of humanity, and is confident that humanity will continue to survive changes and setbacks in the coming decades..