Full Idea
Tarski, a physicalist, reduced semantics to physical and/or logicomathematical concepts. He defined all semantic concepts, save satisfaction, in terms of truth. Then truth is defined in terms of satisfaction, and satisfaction is given non-semantically.
Gist of Idea
For physicalism, reduce truth to satisfaction, then define satisfaction as physical-plus-logic
Source
report of Alfred Tarski (The Concept of Truth for Formalized Languages [1933]) by Richard L. Kirkham - Theories of Truth: a Critical Introduction 5.1
Book Reference
Kirkham,Richard L.: 'Theories of Truth: a Critical Introduction' [MIT 1995], p.142
A Reaction
The term 'logicomathematical' is intended to cover set theory. Kirkham says you can remove these restrictions from Tarski's theory, and the result is a version of the correspondence theory.