Home › Forums › Discuss Introduction to Logic › Check my work please › Reply To: Check my work please
November 14, 2012 at 11:57 pm
#19028
Participant
Jerryb225: Your worked example is correct. Where ‘-‘ stands for a complement:
HAS becomes -SA-H, by contraposition (contraposition valid on O and A types)
-SA-H becomes -SEH by obversion (obversion valid on A, E, I, O)
-SEH becomes HE-S by conversion, (conversion valid on I and E types) and
HE-S becomes HAS by obversion (obversion valid on A, E, I, and O)
I think you’ll agree that it’s not easy to see the equivalency of these four propositions in English!