Abstract

I know that it is difficult for some students to distinguish the truth of premises from the validity of an argument. They think that a valid argument has all true statements, and an invalid one a false premise. Clearly, the teaching of validity requires introducing the idea of an argument form, for it is the form which is the vehicle of validity, not what is put in the form. An argument form does not contain statements (but statement forms), so there is nothing in the form to be true or false. Yet the form has the property of validity, which is the property of truth preservation. This is to say that a valid form will never allow the premise forms to be filled with true statements and the conclusion form to be filled with a false statement.