All living organisms need to be metabolized, otherwise life will stop. Civilization is the same, if it is self-closed for a long time, it will inevitably decline. Communication and mutual learning are the essential requirements for the development of civilizations. Only by communicating and learning from other civilizations and absorbing the strengths of others, To make up for one's shortcomings, in order to maintain a vigorous life.
If a civilization does not exchange and learn from other civilizations, it cannot maintain its vigorous vitality can be derived.