Dictionary of Arguments  
 
S 4 / S 5, logic, philosophy: S 4 and S 5 are modal logical systems that differ in terms of what is expressible in them. The increase in expressiveness is achieved by adding axioms. S 5 results from S 4 by the added axiom Mp > NMp. "What is possible is necessarily possible". See also axioms, axiom systems, modal logic, modalities, stronger/weaker. _____________ Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments.  
Author  Item  More concepts for author  

Bigelow, John  S 4 / S 5  Bigelow, John  
Cresswell, Maxwell J.  S 4 / S 5  Cresswell, Maxwell J.  
