ABSTRACT
Ordinary statements in different composite forms can easily be seen to be equivalent. Consider the following:
I f we write p for Martin is stupid, q for Jones is a bad teacher, and py q for their respective contradictories, we can exhibit the form of these four propositions as follows: (i) Either p or q; (ii) I f p , q; (iii) I f qy p\ (iv) Not both p and q. These are all equivalent to one another and are consequently alike con tradicted by the conjunctive Both p and q.
