- Absolute (in philosophical context)(as used in metaphysics)
- Something that is true or real in itself, independent of any particular framework, perspective, or point of view.
- Continuum Hypothesis (CH)(Used as the central example of an independence result motivating the multiverse view)
- A proposition in set theory whose truth value is independent of the standard ZFC axioms; in the multiverse framework, it holds in some universes and fails in others.
- Ernst Zermelo(as a historical figure in mathematics and logic)
- A German mathematician (1871-1953) who developed foundational work in set theory, which is the mathematical study of collections of objects.
- Ontology(Carnap argues this enterprise is based on a mistake)
- The philosophical discipline that tries to answer hard questions about what there really is.
- Powerset(as used in set theory)
- In mathematics, the collection of all possible subsets of a given set. For example, the powerset of {1, 2} includes {}, {1}, {2}, and {1, 2}.
- Quasi-categoricity(as used in mathematical logic)
- A technical property in logic meaning that a set of rules or axioms describes its subject almost uniquely, with only minor variations possible.
- Second-order logic(as used in mathematical logic)
- A formal system that goes beyond basic logic by allowing you to quantify over (talk about) properties and relations themselves, not just individual objects.
- determinate truth value(supervaluation logic)
- A sentence has a determinate truth value when it is uniformly true or uniformly false across all admissible structures; it lacks a determinate truth value when its truth value varies across admissible structures
- primitive(Used by Merricks to characterize the representational nature of propositions)
- A fact or property that has no further explanation; it cannot be derived from or reduced to anything more fundamental.