Semperism is not a single philosophy or social movement, though it has spawned many of them. Instead it is a broad and loosely connected but highly persistent set of memes in Terragen society. A Semperist is anyone who has given serious thought to the direction of and ultimate fate of Terragen civilization, considering the implications of the Fermi Paradox. Semperists consider the various proposed Great Filters and in light of those what might be done to prolong, preserve, or revive either Terragen society or some fraction of Terragen society against existential threats. It is common for Semperists to take a critical stance towards whatever laws, customs or technologies are identified as possible agents of extinction. At the extreme it might mean proposing that whatever it is be abandoned entirely, but more often Semperists take a more conservative approach that involves advocating thoughtful and analytical use of suspect ideas or inventions. A second common theme of Semperism involves some advocacy of a high degree of self-sufficiency and autonomy for individuals, polities, and other groups who might be left stranded if some or all of the pillars of the current Civilized Galaxy were to collapse. A third common Semperist theme is that they seek to create isolated enclaves either for themselves or others that would allow for survivors, or that they launch projects to create caches and reserves of important information that might allow the re-creation of Terragen society if it falls.
Beyond the broad themes that unite them there is huge variety among Semperists. The wild-eyed and paranoid survivalist living somewhere in interstellar space with a cache of vital supplies and the clear-eyed persuasive analyst living in the thick of the Inner Sphere and working for the ancient and renowned Institute for Survival are both Semperists. The dilettante who makes an affectation of carrying the Encyclopaedia Everythingiana and the serious and dedicated composer and reviser of that same document both call themselves Semperists. Semperism is commonly associated in the public imagination with isolationist bionts, typically humans, who are ordinary sophonts and reject some or many of the Civilized Galaxy's technologies and habits. In fact some of the most dedicated Semperists are virtuals living in highly protected cybercosms, with backup copies of themselves scattered in every datahaven on the Known Net. As for toposophic level, it is notable that Semperists they often have the backing of transapients, and one of the greater archailects (The Eternal) is arguably a kind of Semperist. Semperists are often thought of as beings who disconnect from the rest of Terragen society, or who advocate lower-technology life styles. It is true that a disproportionate number of Hiders, Leavers, and Lo Teks are Semperists, but most of these groups have chosen those lifestyles for other reasons entirely. In fact the majority of Semperists are well integrated members of Terragen society, using all or most of the technologies that are available to sophonts all through the Civilized Galaxy. Good examples of these 'integrated' Semperists would be the creators and the many users of the Encyclopaedia Enverythingiana, or the many Metasoft vecs who have devoted themselves to creating 'backups' of Terragen civilization in the form of the Metasoft Baseline Reserves.
History
Semperism is an old Anglic word. At the time of its origin it was a neologism based on the Old Earth Latin 'semper' for 'always'. It goes back at least as far as the aftermath of the Technocalypse, when Terragenkind had its first unequivocal demonstration that a highly connected and sophisticated set of societies bearing the latest technologies might still be threatened with extinction, possibly as a result of that same sophistication. Few of the survivors of the Solsys disaster were formally Semperists, however; it was merely a common mind-set.
Semperism as a named distinct term and movement became common only with the rise of the First Federation. At that time there were two major thrusts to Semperist thought. On the one hand the Federation's founders were seeking to create a new and more durable meta-civilization, and actively planning to prevent the dissolution of the Federation or any of its members. On the other hand, a small but a vocal minority refused Federation contact and aid and fled further into one form or another of isolation. In such a climate the then relatively young fields of xenology and toposophic studies spurred on these debates, as did fleeting contacts with the ahuman or solipsist ai societies of Terragen origin. Each trace of xenosophont civilizations, and each mysterious mass transcension or discovery of some mysterious artefact spurred more debate, and the term 'Semperist' became well established and there was a flourishing in early Semperist thought.
The first major wave of Semperism faded into the background once the First Federation became well established, but it revived in the 2000's when worries about the durability of the First Federation synthesis came to the fore once more. This lead to the creation of the Semperist Survival Fleet and ultimately to the creation of the Refugium Federation and very probably to a number of other Hider or Leaver civilizations that have still not been discovered. Semperist schools of thought have waxed and waned many times since, becoming more common during such times such as the Version War or the Age of Fragmentation when Terragen civilization's survival and continuity has come into question. Some particular organizations, such as the Institute for Survival, the creator of the Encyclopaedia Everythingiana, have persisted through these changes but most have come and gone. In recent centuries there has been an upswing in uncertainty, and the current crop of Semperist belief systems is sometimes referred to collectively as Neosemperism.