existenciais

Existenciais is the plural form of the Portuguese adjective existencial. In formal fields, it often refers to existential quantifiers, expressions that assert the existence of at least one object satisfying a property. In everyday language, it can also describe themes or questions related to existence, though the standard term for the philosophical movement is existencialismo.

Existential quantifiers are formal devices in logic and formal semantics; they are typically denoted by the symbol ∃ and read as "there exists." For example, ∃x (P(x)) states that there is at least one x such that P(x) holds. They contrast with universal quantifiers, written ∀, which express that a property holds for all elements. In natural language, existential constructions use phrases like "there is/are" in English or equivalent forms in other languages; in Portuguese, verbs such as existir or constructions with há convey similar meanings. In many languages, dedicated syntactic structures express existence and influence scope and entailment in discourse.

Historically, existential quantification was formalized by logicians in the 19th and 20th centuries, with key developments by figures such as Frege and Russell. It later became central to formal grammars, mathematical logic, and computer science. In linguistics and semantics, existentials are studied as a class of expressions that introduce referents into discourse and interact with scope, negation, and focus.

In philosophy and everyday language, the term existenciais may appear in discussions of existential questions—topics concerning meaning, freedom, anxiety, and mortality. These are usually described as questões existenciais, while the broader philosophical movement is called existencialismo. See also existential quantifier, existencialismo, there-expressions.