Awareness, in this technical sense, is a blunt instrument. A refinement was suggested in van Benthem 1991: use explicit knowledge terms. As part of a project to provide a constructive semantics for intuitionistic logic, a formal logic of explicit proof terms was presented in Artemov 2001. Later a possible world semantics for it was created in Fitting 2006. In this logic truths are known for explicit reasons, and these explicit reasons provide a measure of complexity. The work was subsequently extended to a more general family of justification logics, which are logics of knowledge in which reasons are made explicit.