Craig on counterfactual identity

But now you raise a quite different objection aimed specifically at (3). “Before God sticks Fred in second century Tibet wouldn't He have to ascertain that Fred would freely reject the Gospel in all circumstances, not just some of them?” Well, He wouldn’t have to, but that’s my hypothesis. Clearly, God could place a person anywhere He wants in human history, regardless of how that person might freely behave in different circumstances. But my suggestion is that God, being so merciful and not wanting anyone to be damned, so providentially orders the world that anyone who would embrace the Gospel if he were to hear it will not be placed in circumstances in which he fails to hear it and is lost. Only in the case of someone who would be saved through his response to general revelation would a person who would freely respond to special revelation, if he heard it, find himself in circumstances where he doesn’t hear it.

http://www.reasonablefaith.org/site/PageServer?pagename=q_and_a&printer_friendly=1

Pardon me for asking, but isn’t this sort of counterfactual identity blatantly incoherent? The Tibetan Fred has a completely different past. Different genealogy. He doesn't have the same parents or grandparents, &c.

Doesn’t treating possible persons as self-contained units who can be moved forward or backward along the timeline obliterate any notion of historical causation, continuity, and time’s arrow?

Aren’t we the product of the past? How can the same person have a completely different family tree leading up to him and still be him? 

Take three different scenarios:

i) If JFK hadn’t been assassinated, LBJ would not have become president in 1963.

That’s a future counterfactual. The past remains the same up to a certain point, then forks off in a different direction.

This counterfactual is prima facie coherent.

ii) If JFK’s PT-109 hadn’t been destroyed in W.W.I.I., he would not have suffered so much back pain.

This counterfactual does alter something about his past. However, that seems to leave his personal identity essentially intact.

iii) If JFK had been born in medieval Tibet, LBJ would not have become president in 1963.

There’s a sense in which the conclusion is true. But in this case, the counterfactual isn’t changing something merely extrinsic or incidental to JFK’s personal identity. Rather, it’s more like the grandfather paradox–for it’s changing something in the past that’s a necessary precondition for him to exist. That’s intrinsic to his personal identity.

You can’t coherently say, If Joseph Kennedy and/or Rose Kennedy were not his parents, then JFK would have turned out differently in this or that respect. Rather, under that scenario, he wouldn’t turn out at all.