Pilgrim's Denial Of Free Will

Pilgrim’s denial of free will exemplifies the destructive properties of war. Free will is the ability to alter the future, yet the Tralfamadorians believe in predestination. The Tralfamadorians tell Pilgrim that free will is a concept unique only to those on Earth--all the other planets have learned better. Pilgrim is comforted by this, as it helps him deal with the realities of the death in the war, as well as the aftermath of his aging and his own pain. There is no way to change anything, no way to prevent all the death and destruction of the war, and this thought gives Billy comfort.
Billy Pilgrim hallucinates about Tralfamadorians and the alien planet Tralfamadore because he is filled with survivor’s guilt. He feels guilty for doing so