Original sentence: As the absence of extraterrestrial visitors does not categorically prove they do not exist, so the absence of time travelers fails to prove time travel is physically impossible; it might be that time travel is physically possible but is never developed or is cautiously used.Many have argued that the absence of time travelers from the future demonstrates that such technology will never be developed, suggesting that it is impossible.This is a analogous to the Fermi paradox related to the absence of evidence of extraterrestrial life
Edited sentence: As the absence of extraterrestrial visitors does not prove they do not exist, so the absence of time travelers fails to prove time travel is physically impossible; it might be that time travel is physically possible but is never developed or is cautiously used.The absence of time travelers from the future is a variation of the Fermi paradox