Assertions and Hypotheses: A Logical Framework for Their Opposition Relations

Following the speech act theory, we take hypotheses and assertions as linguistic acts with different illocutionary forces. We\r\nassume that a hypothesis is justified if there is at least a scintilla of evidence for the truth of its propositional content, while\r\nan assertion is justified when there is conclusive evidence that its propositional content is true. Here we extend the logical\r\ntreatment for assertions given by Dalla Pozza and Garola (1995, Erkenntnis, 43, 81–109) by outlining a pragmatic logic for\r\nassertions and hypotheses. On the basis of this extension we analyse the standard logical opposition relations for assertions\r\nand hypotheses. We formulate a pragmatic square of oppositions for assertions and a hexagon of oppositions for hypotheses.\r\nFinally, we give a mixed hexagon of oppositions to point out the opposition relations for assertions and hypotheses