Resource Description Framework, RDF, logic puzzle, first order logic, CFL, knowing, believing, deriving

From the web discussion on a difference between knowing and believing, we have chosen in this paper the statements fulfilling enough our seeing the topic, corresponding to our knowledge level of cognitive science. The aim of paper shows one of the capabilities of our Resource Description Framework Clausal Form Logic (RDF CFL) graph language using as an example a well- known Castaněda's puzzle. RDF CFL is an appropriate tool that contains a package of inference methods working especially in closed-worlds that have been developed in the clausal form of first order predicate logics.