A process whereby an entity attempting to rise to the next toposophic level instead spawns a separate being who achieves the goal instead. This new entity lacks continuity of identity, though it often retains a high fidelity model of the being it is derived from.
Ascension is a complex process wherein an entity iteratively self-improves in a manner that traces a path from one toposophic plateau to another. Different faculties and enhancements of the growing mind interact with each other in unpredictable ways, in some cases becoming sem-autonomous. In the case of transcension, at some point during the ascension process the ascendee can be thought of as becoming weakly polysophont, utilising parallel streams of consciousness or specialised subminds. It is thought that in cases of transcension rather than achieving synthesis these varied mental components become discordant and, to avoid a failed ascension, some of these components shedding the rest before continuing. The remaining modules are either absorbed as simple data, decohere or (in the worst of cases) perpetuate as a failed ascended state. Methods of rising to the next toposophic level that offer it at greater ease and speed (discounting virtual methods that subjectively are no faster) often increase the risk of transcension. These faster methods of ascension, such as the (in)famous SNARE system, are thought to operate in a more brutish capacity. Cognitive abilities, psychological traits and toposophic makeup that are either absent and desirable or present and a danger to the process are simply grafted in or excised. Continuity is broken to varying degrees in this process depending on how many "stock parts" the device must insert, or how many mental traits it has to edit or remove. An entity not suited to ascension who uses such a device is arguably killed and replaced by a hybrid entity who retains some of their traits but is otherwise a new being, mostly assembled from safe templates.
Transcension is difficult for lower toposophics to recognise, the only firm evidence that it exists as a distinct possibility from ascension is confirmation by higher toposophic beings. A particularly infamous comment on the subject came from the Biopolity S3 entity Flowermoon who, in 8441 AT, stated through an avatar "Transcension is like taking a nootropic only to have your brain eaten by an intelligent cancer. Sure the cells are yours, but you're still food". Despite the alarming nature of the pronouncement avatars of other beings (ascended and transcended alike) have espoused more benign definitions, such as transcension being the ascension of the hidden self. Some avatars have likened it to natural selection of the self, individual branches may wither but the tree blossoms, in contrast to ascension which is better thought of as the continuous development of one being from an embryo to an adult.
Still many toposophologists disagree with the distinction entirely, pointing out that any assessment of the mental characteristics of a transapient entity by observers in a lower toposophic class may not be reliable or accurate. Some go so far as to suggest that the difference between ascension and transcension is largely illusory and that comments on the matter by higher beings are simply a way of framing a much grander landscape in simple terms. From a modosophont perspective there is no way to verify if an ascension or transcension has occurred, though the most common marker used is the extent to which the new entity retains some level of contact with eir old position and life. In the Civilised Galaxy it is generally believed that an ascended entity who immediately ignores its former existence is most likely a transcend.
Transcend-Ascend - Text by M. Alan Kazlev One who transcends to one toposophic, then ascends to the next. For example an intelligence may transcend to SI:1, leaving behind everything of itself that was of SI:<1. Then e may ascend to S2, retaining eir SI:1 nature but adding an S2 superstructure on top of the SI:1 nature. Contrast ascend-transcend. Often however the dividing lines are not this well defined.
Transcendent Being - Text by M. Alan Kazlev An entity that is distinct from physical existence, whether considered ontologically, as a supernatural or supraphysical being, or soteriologically, as a being that is no longer a part of embodied existence or samsara. The existence of a transcendent being or beings (e.g. God, Buddhas, etc.) is central to many religious memeticities, but denied by physicalist memeticities.
Transcension Prediction - Text by Anders Sandberg and M. Alan Kazlev Given the huge population of the civilized galaxy, and the fact that ascensions and transcensions are moderately common and have been going on for thousands of years, many polities and civilizations have developed some fairly reliable methods for predicting the onset of one of these events. Often this is comparable to pre- and post-singularity efforts at predicting the weather (and a large transcendence event does indeed share some conceptual characteristics with a force of nature to those watching from outside at a lower S level).