Philosophy developed by Academician Athol Kamani on the Dominion world of Mithras during the late Empires period.
Claimed that archailect cultures tend to be perpetual and effectively immortal (lasting as long as the archailect eirself). Perpetualism became a popular historical interpretation during the SecFed era, especially in Dominion and, to a lesser extent, Negentropist worlds. Its reputation was seriously damaged by events of the Version War, which disproved several of its theses (one being that a major interstellar war was not possible in a archailect mediated civilisation). However, following the reconstruction period and with the rise of the ComEmp a number of newer versions of Perpetualism developed. Most of these were forms of "weak Perpetualism" (the most popular being Ngian Perpetualism - which was developed by the Ngist School of Perpetualists on Latimer Habitat), as opposed to the "strong Perpetualism" of Kamani. During the Period of Fragmentation there was a sort of ideological conflict (a few times heating up to a memetic war on some worlds) between Ngian Perpetualism and Sabinian Kalyptism, the former indicating a more or less stable civilization, the latter predicting a coolapse of the established order.
Different schools of Perpetualism are very interested in xenopaleological research, trying to find out whether extinct aliens had archailects.