Abstract

This chapter provides a brief version of the mathematician Brandon Carter's “doomsday argument”, a probabilistic argument that attempts to predict the future lifetime of the human race given an estimate of the total number of humans born thus far. It challenges Carter's argument by stating the crucial point that we ought (until we find enough contrary evidence) to try to see ourselves as “fairly ordinary” inside the various classes into which we fall ‐ bearing in mind, naturally, that in some cases there might be tradeoffs to be made because being more ordinary inside one class might involve being less ordinary inside another. Even if humans were statistically very unusual among all observers scattered through space and time, observers falling into vastly many different species, there might still be nothing too odd in being a human rather than a member of some other intelligent species.