(JINRUI HOKAN KEIKAKU) A plan to
artificially evolve humanity which had reached its limit as a
colony of flawed and separate entities, into a
perfect single being. It was promoted under the direction of
SEELE, with Special Agency
NERV as the implementing organization. However, it seems that SEELE's objective differed from that of NERV -- that is to say of
Gendou Ikari and
Kouzou Fuyutsuki. The
Evangelion was not actually built as a
weapon, but instead with the aim of realizing this (
Instrumentality) project. Specifically, this appears to have been a project to artificially initiate
Third Impact, thus
eliminating all of humanity who, after shedding their
human forms, would then
evolve to a new stage.
Source: The End of Evangelion : Glossary contained within The End of Evangelion - Theatrical Program.