The Doomsday argument does "not" say that humanity cannot or will not exist indefinitely. It does not put any upper limit on the number of humans that will ever exist, nor provide a date for when humanity will become extinct. An abbreviated form of the argument "does" make these claims, by confusing probability with certainty. However, the actual conclusion for the version used above is that there is a 95% "chance" of extinction within 9,120 years, and a 5% chance that some humans will still be alive at the end of that period. (The precise numbers vary among specific Doomsday arguments.)