What Is An Argument?

An argument is a set of statements, of which one is the conclusion and the rest are the premises. In a deductive argument, the conclusion is necessarily true based on the premises; for example, If you spin in circles, you get dizzy. You are spinning. Therefore, you are dizzy. In an inductive argument, the conclusion is likely true most of the time. For example, If you spin in circles, you will likely get sick. You are spinning. Therefore, you will likely get sick.

An argument is valid if and only if it is impossible for its premises to be true and the conclusion false. An argument is sound if and only if it is valid and its premises are all true. A sound argument invariably has a true conclusion. An argument is strong if and only if it is improbable for the premises to be true and the conclusion false. An argument is reliable if and only if it is strong and its premises are all true. Soundness is to validity what reliability is to strength.

An inductive argument is strong rather than valid. Therefore, not every invalid inductive argument is a failed argument. An inductive argument is as reliable as it is strong, and as failed as it is weak. The major valid deductive argument forms involve truth-functional operators, universal quantifiers, existential quantifiers and identity. The most used strong inductive argument forms include Enumeration, Statistical Syllogism, Analogical Syllogism and Inference.