This drawing-together of the different peoples out of their earlier isolation, which modern civilization has brought about, has not only increased their knowledge of each other but also increased their effect upon the lives and fortunes of one another. Out of this has grown the complexity of contemporary political, economic, and racial problems. What one nation does is liable to affect not only its neighbours but also far-away nations to the point of actual war. Therefore, there is much greater need of learning for what purpose all the human race has been placed on this earth than there was in earlier and more isolated times.
-- Notebooks Category 11: The Negatives > Chapter 3: Their Presence in The World > # 374