Question

What rules of inference are used in the given below argument? "no man is an island. manhattan is an island. therefore, manhattan is not a man."?

Answer 1

There are three rules of inference are used in the sentence.

1) Universal Instantiation, if x is a man, then x is not an island” and “If Manhattan is a man, then Manhattan is not an island.”

2) 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.