Is Peter fatalistic?

Is Peter fatalistic? No. But he does demonstrate the same fatalism as Jeanie. He hates his family, and probably people too:

I content myself to think that one day we will all be nothing but marks in stone. Iron stains of blood, black of our carbon, a hardening clay.

Jeannie looks back when she scorns the human race, and her children:

They could not seem to grasp that what mattered was what you did. Not what you said or thought about.

She characterises the weakness of the younger generation as "slackening":

But the slackening. By fire she and her brothers were throwing hoops. By ten she was at the branding fire.

Eli's life was much the same, and his view of his place in the world echos Jeannie's opinion of men:

It was not that I did not love my family. But there are things no person can give you.

There is a subtle difference between Jeannie's view and Eli's view. For Eli the fire that "burns for him alone" is not a self-obsessive thing, but something natural. His descendents think of him as living naturally: relishing in the destruction of his enemies. We can see the progress from Eli's view of individualism to Jeannie's skeptical, feminist view as representative of the changes over the generations, from Eli to Susan. It seems this is a major goal and success of the novel. What we see, in fact, is not deterioation but the many and subtle effects of the needs of living on the character of a human being. Eli grew up killing and stealing. Susan grew up with cartoons. Eli is violent and hateful as an old man, Susan is weak and good at nothing. In seeing how these characters unfold, and realising how molded they are by their worlds, I'm finding that neither deserves judgement.