How did Rudolf Carnap’s artificial languages use syntax and semantics?

Rudolf Carnap believed that philosophical perplexities could be resolved through the "logical analysis of language," which required moving beyond ordinary usage to the use of artificially constructed languages. These artificial languages were formulated using logical symbolism and governed by precisely specified rules of syntax and semantics.1

• Syntax: Carnap’s syntactical studies focused on the purely structural features of a language, specifically its formation and transformation rules. In this dimension, one abstracts from the meanings of expressions to study only the relations between them.23
• Semantics: Carnap later incorporated semantical studies, which concern rules of designation and truth. Semantics allows for the analysis of expressions and their meanings by abstracting from the language user. By defining truth conditions for sentences within a formal system, Carnap identified the meaning of a sentence with its truth condition—the necessary and sufficient conditions under which a sentence would be true.23

Together, these rules provided a rigorous framework for logical reconstruction, allowing for the clarification of technical issues in science and mathematics that ordinary language could not adequately address.12