A note on the Doomsday Argument

Abstract

I argue that advocates of the Doomsday Argument are faced with a dilemma. If they accept the thirder position regarding self-location, then the Doomsday Argument fails; knowledge of birth rank has no effect on one’s credences concerning the survival of the human species. If they accept the halfer position regarding self-location, then the Doomsday Argument fails; knowledge of birth rank may confirm smaller total human populations over larger ones, but this is not equivalent to confirmation of a shorter future for humanity, and in fact the same evidence may confirm longer future human survival over shorter.