# Thread: conditional proof

1. ## conditional proof

Use a conditional proof to prove the following argument:

Only a fool would lie about one of Elaine's sorority sisters to her. A classmate of
Elaine's lied about Joanne to her. Therefore, if none of Elaine's classmates are fools, then Joanne is not a sorority sister of Elaine. (F(x) = x is a fool; L(x,y,z) = x lies
about y to z ; C(x,y) = x is a classmate of y; S(x,y) = x is a sorority sister of y;
e = Elaine ; j = Joanne)

Any help? Thanks!

2. Originally Posted by LCopper2010
Use a conditional proof to prove the following argument:

Only a fool would lie about one of Elaine's sorority sisters to her. A classmate of
Elaine's lied about Joanne to her. Therefore, if none of Elaine's classmates are fools, then Joanne is not a sorority sister of Elaine. (F(x) = x is a fool; L(x,y,z) = x lies
about y to z ; C(x,y) = x is a classmate of y; S(x,y) = x is a sorority sister of y;
e = Elaine ; j = Joanne)

Any help? Thanks!
Have you tried anything for that problem??