“Speech is civilization itself. The word, even the most contradictory word, preserves contact – it is silence which isolates.”

What I say to myself forms the boundaries of my world.  Living is a form of dialogue with the world, within and without, worlds within worlds. 

The 'civilized' world is the world of people in dialogue with each other.  This dialogue forms 'our' world.  Whether an individual or a group discovers a previously unknown truth, its revelation challenges perceptions and tears down worlds. 

In other words, I am saved from living in a delusional world by others, and vice versa.  A people silent towards each other are indeed in their own worlds.