There is always a reason whatever that may be. But thoughts are funny for some reasons just do not make sense.
I will use myself as an example. And this is the bubble of my thoughts.
I post. I trash. I post. I trash. Repeat.
Can I anticipate the maddening process of my brain? Yes, most of the time.
I wonder if Hemingway’s bubbling thoughts is similar to me. Did he learn to forgive?
Photographs and Memories 
I don’t think he did. Otherwise he wouldn’t kill himself, would he? (His wife said he was cleaning weapon).
I am sure he does now 😉
Good one, Helen. For all the genius in him, it tormented him in the end or maybe due to vitamin A he ingested. That is Alcohol.