There are three <span>rules of inference are used in the sentence.</span>
<span>1) </span><span>Universal Instantiation, if x is a man, then x is not
an island” and “If Manhattan is a man, then Manhattan is</span> not an island.”
<span>2) </span>Contrapositive,
If Manhattan is an island, then Manhattan is not a man.”
3) Applying
modus ponens or modus tollens. We derive the result that Manhattan is not a man.
