Whats the only thing the people call theirs own? Does it stay true throughout the story? Does it stay true throughout the story?

One of the
premises of this book is that reality as we think of it does not exist.  As long as you cling to
an "objective" reality, you are deceived.  If you continue to truly believe that 2 + 2
= 4, you are deceived because in their world 2 + 2 = anything the party wants it to be.  This is
mirrored in their treatment of the past where it has no objective reality, but is anything that
the party says it is/has...