To write too much about the plot and this afterlife of Ness's creation would be to ruin the experience of reading the book (which I highly recommend), so I'm going to focus on a few of the life philosophies of some of the characters. Ness weaves these philosophies not so much for the reader to choose one, but for the reader to become aware of some of the many complex ways people use to make their way through life, as Seth faces both his current life and what he finds as both of his former lives and attempts to cull meaning from each of them.
The hopeful. Seth's friend and first love Gudman says multiple times throughout the book in Seth's memory: "There's always beauty if you know where to look." This phrase haunts Seth in his deepest moments of pain.
The seeker of meaning and the cynic. Seth spends much of his time in the afterlife trying to figure out a greater narrative for what is happening to him. Regine, one of the two people he meets there says: "People see stories everywhere...That's what my father used to say. We take random events and we put them together in a pattern so we can comfort ourselves with a story, no matter how much it obviously isn't true. We have to lie to ourselves to live. Otherwise we'd go crazy."
The escapists. When his parents are considering a scientific, virtual escape from their lives after a tragedy Seth father shares: "You mean Lethe. The river of forgetfulness in Hades. So the dead don't remember their former lives and spend eternity mourning them."
This brings us back to the title--there must be More Than This. There are parts of life that seem to make no sense and we must seek to find answers. We must know the present reality isn't always the only truth. Ness seems to be saying the answer doesn't lie within a singular philosophy, but in a complex matrix. The older I've gotten, the more I appreciate openness to mystery and the more I've started accepting living in uncertainty. That doesn't mean I don't have some anchors set down in a few key places, just that this life is so much bigger than I ever imagined.