Constructive dilemma is a logical rule of inference that says if P implies Q, R implies S, and P or R is true, then Q or S is true as well. Essentially, the constructive dilemma passes the disjunction through two conditional statements. For example, if the statements
“If I am running, I am happy.”
“If I am sleeping, I am dreaming.”
“I am running or sleeping.”
are true, then it must also be true that I am happy or I am dreaming.