You are assuming that there cannot be a culture with value so different that being adult does not have any meaning for it. Of course it would be rather short li

You are assuming that there cannot be a culture with value so different that being adult does not have any meaning for it. Of course it would be rather short lived one (without new children its hard for any culture to propagate). Ultimately it comes to simple systemic truth - the value of adulthood comes from its usefulness for culture survival - so in I believe it does not have any intrinsic value (its only valuable from the point of view of survival of culture).