Logical Arguments - Modus Ponens & Modus Tollens

Modus Ponens and Modus Tollens are two logical argument forms. In either case, these have two premises and a conclusion. These argument forms are called valid, which means that if you accept the hypotheses, then it is valid to conclude the conclusion. This is distinct from having a sound argument which means not only is the structure logically valid, but additionally the premises are true. In this video we will learn how to analyze a written argument by its logical structure, as well as write out the truth table for Modus Ponens and Modus Tollens.

Modus Ponens:
if p, then q
p
Therefore, q

Modus Tollens:
If p, then q
Not q,
Therefore, Not p.

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