Definition
Argument
An argument is a collection of formulas called premises together with a formula called the **conclusion.
Goodness
Definition
Link to originalGood Argument
A good argument is a valid argument whose premises are true.
In other words, a good argument is not only logically correct, but also starts from acceptable assumptions.
Argument vs Formula
A formula is a single well-formed expression. It can be evaluated as true or false under an interpretation.
An argument is not a single formula. It is a structure made of several formulas: the premises and the conclusion.
So validity, contradiction, and satisfiability are properties of formulas, while validity, goodness, and soundness are properties of arguments.