universethat

Universethat is a neologism used in speculative cosmology and science fiction to describe a meta-framework for comparing potential universes. The term emphasizes how a universe is defined by its defining criteria—such as physical laws, dimensionality, initial conditions, computational substrate, or the presence of observers—rather than by a single narrative or content. The phrase is not a formal scientific term; rather, it appears in online discussions, thought experiments, and fiction as a shorthand for discussing variations of the cosmos.

In practice, universethat can be used to classify universes into categories such as physically realized universes with consistent laws, simulated universes running on computational substrates, and narrative universes whose consistency rests on internal storytelling rules. Some discussions pair universethat with broader multiverse concepts, drawing analogies to models that attempt to enumerate or contrast possible realities. The approach invites philosophical questions about underdetermination, the status of laws, and what constitutes a separating criterion between universes.

Critics note that universethat is speculative and depends on contested assumptions about laws, reality, and observation. Proponents argue that it helps clarify discussions about what could count as a distinct universe and aids in organizing ideas in both scientific and literary contexts.

See also: multiverse, simulation hypothesis, modal realism, Tegmark's levels of the multiverse, speculative fiction.