I wrote a paper in logic class on disjunctive addition, P, therefore P v Q. I wanted to argue that if we then take P v Q in the EXCLUSIVE sense, the following is possible: we can CHANGE the truth value of P v Q. If, say, P is the statement "JFK is dead" and we conclude by disjunctive addition that "JFK is dead(P) or south main st. is wet(Q,) and if we now assume Q is true, the whole disjunct is false (since in disjuctive addition exclusive sense if both disjuncts are true the entire disjunct is false)

I then argued that we CAN change the truth value of P v Q just by steaming south main st(or wait for the sun to dry it)

But my logic teacher says I've misunderstood disjunctive addition in the exclusive sense.

Can anyone help? I'm a college sophmore

Thanks