[3] In 1955 Mary and Arthur Prior recalled Whately's suggestion for a variable copula to write questions symbolically.
Steel Jr. wrote The Logic of Questions and Answers (1976),[7] which came at a watershed moment: while purportedly continuing the philosophical investigation of Harrah, they anticipated query languages and data base management systems.
[8] Some contributions in this direction are Jaakko Hintikka's interrogative model and Andrzej Wiśniewski's inferential erotetic logic (IEL).
In 2011 Anna Brożek published The Theory of Questions which started with philosophical context (ontology, epistemology), then use in human intercourse, with a consideration of cognition and answers.
Embedded questions and situational analysis are noted, as well as specific considerations with regard to science, psychology, and surveys.
Concluding chapters consider legal proceedings, philosophical questions, and the history of erotetic study in Poland in the 20th-century.