"We Can Have Never Been"

"We can have never been..."
"The Year Of The Ransom" IN Time Patrol, p. 679.

What can this statement by Manse Everard mean?

(i) A timeline in which we never existed is possible. OK.

(ii) A timeline in which we never existed might coexist with the timeline in which we do exist, might diverge from it or run in parallel with it. OK.

(iii) There might be a temporal succession of timelines such that a timeline in which we never existed succeeds/will succeed this timeline in which we do exist. OK.

(iv) Within a single timeline, a man might exist from his birth until the age of 30, then, on reaching that age, cease to have existed from his birth until the age of 30. No. Impossible. Absurd. Contradictory. Everard cannot mean this.