Greg Egan is one of the few authors whose books I can re-read and Arrows of Time certainly rewards re-reading. The first time, through, it was all I could do to keep track of the “human” story (they’re actually squishy, alt-universe Barbapapa-people). This second time, I could spend my mental energy trying to wrap my mind around time moving in different directions.
It should tell you something that the whole “what of free will in a deterministic universe” problem gets about a paragraph before it’s solved and we move on to other, more interesting exercises. Such as determining whether the cosmos has positive or negative curvature.
And that’s all layered on top of a discussion about our desperate search for meaning in a cosmos that assures us it has none. The balance between what we must and must not know. The terror we have for the part we play in making the future. What will I discover on my next read-through?