Perhaps civilisation is only whatever we think of as normal, or perhaps it’s the baseline normality we’re born into. It’s a series of expectations that shifts forward with each generation. A series of technological landmarks to tick off the list: electricity, refrigeration, the internet. The higher we climb, the further we fall. So, if your world had been through the sort of upheaval that knocks your definition of civilisation back several generations, what level do you aspire to rebuild to? What is the civilisation you construct from the ruins you find yourself in?
