Symbolic Logic I

Statement Forms and Substitution Instances


Every WFF is a substitution instance of a statement form.  Here are two lists, one of statement forms, the other of WFFs.  Identify each of the statement forms of which each WFF is an instance, remembering that a WFF may be a substitution instance of more than one statement form.


Statement Forms  WFFs

a.                   p

b.                  ~p

c.                   p q

d.                  p q

e.                   ~(p q)

f.                    ~p q

g.                   ~p (q r)

h.                   (p q) r

i.                     p q

j.                    ~(p q)

k.                  ~p (q r)


1.         A B

2.                  P (Q R)

3.                  ~P (Q R)

4.                  P (Q R)

5.                  ~[(P Q) R]

6.                  (P  Q) (R ~S)

7.                  ~P (Q R)

8.                  P (Q R)

9.                  {[P (Q S)] R} P

10.              ~(Q R) ~(R S)

11.              {[P (Q S)] R} P

12.              ~(P Q) R

13.              ~[P (Q R)]

14.              ~[~P (Q R)]