Demonstrating Invalidity

Study two techniques for demonstrating that an argument in first-order predicate logic is invalid. The method of counter... (more)

Study two techniques for demonstrating that an argument in first-order predicate logic is invalid. The method of counter-example involves scrupulous attention to the full meaning of the words in a sentence, which is an unusual requirement, given the symbolic nature of logic. The method of expansion has no such requirement. (less)