As anyone who is familiar with the Isaac Asimov's Robots in Time series by William F. Wu is already aware, the Mojave Center Governor does not realize that sending his component parts backwards through time results in nuclear explosions and thus erasing them from history. Once the human/robot team is created to travel back in time to to retrieve the components, how does this not introduce a grandfather paradox such that the components would never have existed in that time period once they are collected?

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    How would that cause them never to have existed? They retrieve the components after they arrive. The personal timeline of the components and the team is still linear; it never crosses over itself, as far as I can remember.
    – SaintWacko
    Commented Sep 20, 2012 at 13:47
  • I don't understand how that would violate the grandfather paradox based on how you described it, to me it seems that they sent a part to the past, realized sending it back in time was a mistake, and send in a team to retrieve the parts in the past, at no time did they do anything that would have made them not send the parts to the past
    – Dave
    Commented Oct 31, 2023 at 21:20

1 Answer 1


I think SaintWacko has the answer, but this question has gone unanswered for 10 years.

The grandfather paradox is two pristine cases of event A and event not-A, where event not-A + time-travel generates event A, and event A + time-travel generates event not-A.

It is a loop: "state A" leads to "state not A" leading back to "state A" again

They inserted a second transformation into sequence such loop that did not generate state not-A, aka they removed the nuclear explosion. That stops it from being that type of loop.

"state A" leads to "state not A" but does not back to "state A" anymore, instead flowing to "state B"

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