Usul-ul-Kalaam is a more specific subfield that focuses on the methodology, principles, and tools used in Ilm-ul-Kalaam. It outlines how theological discussions and arguments should be structured, what methods are valid for deriving conclusions, and the rules governing theological debates. In essence, Usul-ul-Kalaam is about the foundational principles that guide the discipline of Ilm-ul-Kalaam.
Google