The Doomsday Argument points not to an imminent end, but to a debate over whether mind uploading counts as death

In Josh Snyder’s model, the median date of “doomsday” is 2919

On August 16, Josh Snyder published an essay on the Doomsday Argument on LessWrong. In his model, 118 billion people born to date and 132 million births per year produce a median “doomsday” date of 2919. The probability of this outcome occurring by 2100 is 8%.

The Doomsday Argument assigns a number to every human birth. Snyder treats a person’s position in this sequence as approximately random. If that position falls near the middle, as many births remain as have already occurred. He then uses the annual number of births to convert the expected remainder of the sequence into a calendar date.

This explains the difference between the historical examples. For 1965, Snyder assumes 120 million births per year and annual growth of 2%. In that version, the median date is 2085. In the current version, 118 billion people born to date and 132 million births per year shift it to 2919. The formula converts the selected demographic inputs into a date.

Snyder then considers scenarios that change the way human life continues. These include digital brain emulation, meaning a program that reproduces the brain’s operation on a computer, AI successors, and the emergence of a genetically engineered human species. In these scenarios, the sequence of biological births may end, while the future of human society, personal experience, and the species’ biological lineage become three separate questions.

One possible path appears in a scenario involving the gradual transfer of brain functions to a computer. The functions are transferred one by one while the original brain continues to operate. This scenario requires a specific criterion for determining whether personal experience persists when its physical substrate changes.

Demographic arithmetic counts births. Determining whether a person dies when their physical substrate changes requires a separate criterion for the preservation of personal experience.