Categorical Prepositions Converse, Inverse, Obverse, Contrapositive YouTube Lecture Handouts

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Categorical Prepositions: Converse, Inverse, Obverse, Contrapositive - Logic

Categorical Prepositions Converse, Inverse, Obverse, Contrapositive

  • Obverse will always be valid form
  • Converse is not valid in A & O
  • Contrapositive is not valid in E & I

Cases –

  • All S is P
  • Converse – All P is S
  • Obverse – No S is non P
  • Contrapositive All non P is non S
Categorical Prepositions
  • Obverse will always be valid form
  • Converse is not valid in A & O
  • Contrapositive is not valid in E & I

Cases –

  • All S is P
  • Converse – All P is S
  • Obverse – No S is non-P
  • Contrapositive all non P is non S
  • Valid if P exists
  • Converse of A - Some P is S
  • Converse of E – Some P is not S

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