[ExI] Time travel brainscans

[Adrian Tymes]

A thought experiment:

Assume that, some centuries in the future, time travel is invented but
it is the "you already did that" type: anything that future people do
in the past, was already done in the past.  They can for instance
record information that would have (appeared) lost, but for instance,
no assassinating Hitler before history recorded his suicide.

So, they get to brainscanning every human who has been alive, just
before their death, with an eye toward resurrection.  They have some
cutoff for what counts - e.g., any embryo that does not make it to
sustained survival outside of/independent from the womb likely
wouldn't be scanned, and the cutoff might be somewhat later.  Homo
sapiens only; the exact boundary depends on historical snapshots they
take to determine the exact path by which the species arose.  There
might be some cases that are beyond their initial capability; these
get flagged for later.

Some current estimates of how many humans have ever lived come in a
bit over 100 billion.  Let us assume it is no more than 150 billion -
not counting those then alive, who can be scanned without time travel
- by the time of this project.  If they can achieve an average pace of
100 scans per worker per day - 4.8 minutes per scan on average - and
assuming 250 working days per year, a workforce of a million (not
counting oversight/coordination and other support personnel, but
likely less than 1.1 million including them) could get this done in 6
years, likely a little longer due to inefficiencies and time to hunt
down hard-to-find cases.

This would be well within the scope of large human projects.  A
workforce that large would almost certainly divide up by interest -
these people focus on the ancient Roman era, that group takes on North
and South America up to somewhere around first European contact (aside
from the Vikings) - so long as overlaps are sorted and unaddressed
areas taken care of eventually (likely toward the end of the project).
Actual resurrection might be handled by another group, perhaps in
batches including orientation of historical people to then-modern
society.

This might explain the phenomena sometimes reported, of near-death
people experiencing going through a tunnel only to perceive some
consciousness saying it is not their time and sending them back to
life.  Or it could be just random musing, of no more impact on reality
than the particulars of a typical dream.