Lexicon of Arguments

 

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Synonymy/Criteria/propositional identity/Geach: we know that strict reciprocal implication is not a sufficient criterion for synonymy.
E.g. "Necessarily either both, p and q, or neither p nor q" usually does not suffice: that does not justify the conclusion: Everyone believes that p if and only if he believes that q".
((s) because of lack of identity criteria for intensional objects.)
>Identity criteria, >Intensional objects.
Geach: entailment as a substitute for strict implication is complicated, but does not help.
>Entailment/Geach.
Transitivity must be abolished - even from reciprocal entailment, the identity of propositions does not follow.
>Transitivity.
Geach: no one knows what he says when he says that two propositions are identical.
>Propositions, >Intensions, >Objects of thought.
If the difference between two propositions is not an obstacle, that both are believed at the same time, why should it be an obstacle being expressed simultaneously by one and the same proposition? - Problem: then the whole apparatus of synonymy and non-ambiguity threatens to collapse. On the other hand, if we cannot recognize the same meaning (sense) in different linguistic disguises, there is also little purpose in postulating propositions.