it made things make a lot more sense to me.  It's one of those books: I have no idea how true these theories are,

Clue in italics.  Explanatory power is always preferred, other things being equal. The brief description given in the diary accords with what I have read in the science press over the last 30 years.  Strong emotion has always been shown to be associated with strong emotion.  Recent PET scan work on active brains has shown the involvement of the limbic system, associated with emotion, in ongoing formation of memory.  Sorry, I don't have references.

"It is not necessary to have hope in order to persevere."