The book Jacob was reading "everything that rises must converge" title is a reference to Teilhard de Chardin. I looked him up and found this.
"Teilhard re-interpreted many disciplines, including theology, sociology, metaphysics, around this understanding of the universe. A main focus of his was to re-assure the converging mass of humanity not to despair, but to trust the evolution of consciousness as it rises through them."
I think this could refer to the progress of humanity that Jacob was talking about on the beach. The evolution to a higher consciousness that eventually culminates to the "One" consciousness. And drives out the ego. Maybe The guy in black on the beach is the ego part of Jacob's consciousness (which causes all the suffering) and he is trying to progress to enlightenment and drive humanities ego out, and thus end human suffering.
"Teilhard re-interpreted many disciplines, including theology, sociology, metaphysics, around this understanding of the universe. A main focus of his was to re-assure the converging mass of humanity not to despair, but to trust the evolution of consciousness as it rises through them."
I think this could refer to the progress of humanity that Jacob was talking about on the beach. The evolution to a higher consciousness that eventually culminates to the "One" consciousness. And drives out the ego. Maybe The guy in black on the beach is the ego part of Jacob's consciousness (which causes all the suffering) and he is trying to progress to enlightenment and drive humanities ego out, and thus end human suffering.