Return again to the original version of the Grandfather paradox and Lewis’s ‘commonplace reasons’ response to it.  This response engenders a further objection.  The autoinfanticidal time traveller is attempting to do something impossible (render herself permanently dead from an age younger than her age at the time of the attempts).  Suppose we accept that she will not succeed and that what will stop her is a succession of commonplace occurrences.  The previous objection was that such a succession is improbable.  The new objection is that the exclusion of the time traveler from successfully committing auto-infanticide is mysteriously inexplicable.  The worry is as follows.  Each particular event that foils the time traveller is explicable in a perfectly ordinary way; but the inevitable combination of these events amounts to a ring-fencing of the forbidden zone of autoinfanticide—and this ring-fencing is mystifying.  It’s like a grand conspiracy to stop the time traveler from doing what she wants to do—and yet there are no conspirators: no time lords, no magical forces of logic.  This is profoundly perplexing.  Riggs (1997, 52) writes: “Lewis’s account may do for a once only attempt, but is untenable as a general explanation of Tim’s continual lack of success if he keeps on trying.” Ismael (2003, 308) writes: “Considered individually, there will be nothing anomalous in the explanations…It is almost irresistible to suppose, however, that there is something anomalous in the cases considered collectively, i.e., in our unfailing lack of success.” See also Gorovitz (1964, 366–7), Horwich (1987, 119–21) and Carroll (2010, 86).