Illucidus

Illucidus is a term used primarily in philosophy and linguistics to describe statements, arguments, or phenomena that lack clear meaning or logical transparency. It denotes a level of semantic opacity or definitional vagueness that hinders straightforward analysis. As a neologism, illucidus may function as both an adjective and a noun in scholarly writing, with an illucidus proposition being one that resists standard criteria for clarity.

Etymology: The word is formed from the Latin lucidus, meaning clear, with a negative prefix-like formation common in English neologisms. Its first documented uses appear in late 20th-century discussions of clarity in argumentation.

Philosophical usage: Illucidus is employed to flag terms or claims that do not meet explicit criteria for definitional transparency, such as ambiguous predicates, shifting conventions, or unresolved presuppositions. Proponents of precision in analysis advocate reformulating or constraining illucidus content, while some scholars argue that certain illucidus aspects reflect genuine ambiguity inherent to natural language rather than modifiable faults.

Linguistic relevance: In linguistics, illucidus is used when addressing semantic opacity, polysemy, and context-dependent meaning. The concept helps distinguish between statements that are unclear by design and those that are unclear due to features of language, often necessitating pragmatics or contextual interpretation rather than formalization.

See also: Lucidity, Obscurity, Vagueness, Ambiguity, Semantic opacity.