Full Idea
For a language, we must enumerate the primitive terms, and the rules of definition for new terms. Then we must distinguish the sentences, and separate out the axioms from amng them, and finally add rules of inference.
Gist of Idea
A language: primitive terms, then definition rules, then sentences, then axioms, and finally inference rules
Source
Alfred Tarski (The Establishment of Scientific Semantics [1936], p.402)
Book Reference
Tarski,Alfred: 'Logic, Semantics, Meta-mathematics' [Hackett 1956], p.402
A Reaction
[compressed] This lays down the standard modern procedure for defining a logical language. Once all of this is in place, we then add a semantics and we are in business. Natural deduction tries to do without the axioms.