death-equivalent existence: It is a cliché, at least among Imperials, that “there are no fates worse than death”. A living sophont, after all, possesses the capacity for choice and action, and thus to better their situation – or, failing that, at least the capacity to be acted upon, in ways that open up further options.

Death, however, terminates your worldline, thus foreclosing all futures.

The term “death-equivalent existence” refers to alternate scenarios which also foreclose all futures. Almost all of these are hypothetical, as it is exceptionally difficult to construct a scenario that is as effective as foreclosing futures as nonexistence, with the accepted candidates being irreversible p-zombification, event horizon suspension, and terminal cases of fulfilled automatomania (q.v.).

The informal term “delta-death scenarios” has arisen to describe those cases which, while not meeting death-equivalency criteria, nonetheless skim very close to them.

– A Star Traveler’s Dictionary