Around and Beyond the Square of Opposition

Part of the series Studies in Universal Logic pp 119-127

Two Concepts of Opposition, Multiple Squares

  • John T. KearnsAffiliated withDepartment of Philosophy and Center for Cognitive Science, University at Buffalo, the State University of New York Email author 

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This paper uses the resources provided by systems of illocutionary logic to characterize an opposition among assertive illocutionary acts that is parallel to incompatibility or inconsistency among statements. It is argued that opposition, or incoherence, among assertive illocutionary acts is more fundamental than inconsistency, and that our understanding of incoherence “underwrites” our conception of inconsistency. Diagrams are provided to illustrate relations of incoherence that are like such traditional diagrams as the square of opposition, which displays relations among statements.


Illocutionary logic Speech acts Logic of speech acts Inconsistency Incoherence

Mathematics Subject Classification

03B42 03B60 03B80