This document presents an introduction to rules of inference and logical arguments. It defines an argument as a sequence of statements ending with a conclusion, and premises as the statements preceding the conclusion. Two main valid rules of inference are then described: modus ponens, where if a conditional statement and its hypothesis are true then the conclusion must be true; and modus tollens, where if a conditional statement is true and the conclusion is false, then the hypothesis must be false. Examples are provided for each. Finally, two common fallacies - affirming the conclusion and denying the hypothesis - are explained.