Language, Logic, and the Brain

Although linguistics may treat languages as a syntactic and/or semantic entity that regulates both language production and comprehension, this article perceives that language is a physical and a biological phenomenon. The biological view of languages presents a new metaphor on an evolutionary time-scale the human brain and human language have co-evolved. Therefore, the brain is the instrument with a repository of syntactic and semantic constraints. The logical vocabulary of natural languages has been understood by many as a purified abstraction in formal sciences, where the internal transactions of reasonings are constrained by the logical laws of thought. Although no vocabulary can be entirely independent of semantic understanding, logical vocabulary has fixed minimal semantic content independent of context. Therefore, logic is centered in linguistic evolution by observing that all connective vocabulary descends from lexical vocabulary based on spatial relationship of sentences. Far from having fixed minimal semantic content, logical vocabulary is semantically rich and context-dependent. Many cases of mutations in logical vocabulary and their semantic changes have been observed as similar to that of biological mutations. These changes proliferate to yield a wide diversity in the evolved uses of natural language connectives.