Dependent and Independent Reasons

Abstract

How are dependent (or linked) premises to be distinguished from independent (or convergent) premises? Deductive validity, sometimes proposed as a necessary condition for depende'nce, cannot be, for the premises of both inductive and deductive but invalid arguments can be dependent. The question is really this: When do multiple premises for a certain conclusion fonn one argument for that conclusion and when do they form multiple arguments? Answer: Premises are dependent when the evidence they offer for their conclusion is more than the ordinary sum of their probabilities. Ordinary sums are defined in the paper.