ABSTRACT
Proof is a complex notion. In simplest terms, a proof is a valid argu-ment with true premises. This is the standard notion of proof inlogic. An argument consists of premises intended to provide support for a conclusion. An argument is valid if it is logically impossible that the premises be true and the conclusion be false.1 Any argument of the form If A then B, A; therefore B, for example, will be valid.
