 The logical analysis of information includes fruitful reinterpretations of known logical systems (such as epistemic logic or relevance logic), and new systems that result from attempts to capture further aspects of informational. Still other logical approaches to the analysis of information result from combining aspects of two different stances, as with the constraint systems of  section 4.  New frameworks (situation theory in the 80s) have also resulted from exploring from scratch what sort of inferences—including those that are novel and non-classical—one should allow in order to model certain aspects of information. 