PHIL 109 Lecture Notes - Lecture 12: Obversion

• School: Marymount
• Department: Philosophy
• Course: PHIL 109
• Professor: Carrie-Anne Biondi

Document Summary

*please note that dr. conard is taking a leave of absence and the course will now be instructed by professor carrie-ann biondi* Additional square of opposition/ immediate inference exercise distributed in class. Subalternates: when the universal (a,e) is true, the particular (i,o) is true. When the universal is false, the particular is false. However, the particular never determines the validity of the universal. Contraries: cannot both be true, but could both be false. If one is true, the other must be false. Subcontraries: cannot both be false, but could both be true. Contradictories: if one is true, then the other must be false. Both cannot be true, and both cannot be false. A: all s is p changes to all p is s (invalid) E: no s is p changes to no p is s (valid) I: some s is p changes to some p is s (valid)