  If we focus on just the simplest kinds of deduction, Aristotle’s procedure comes quickly into view.   The perfect deduction already presented is an instance of universal affirmation: all As are Bs; all Bs Cs; and so, all As are Cs. Now, contends Aristotle, it is possible to run through all combinations of simple premises and display their basic inferential structures and then to relate them back to this and similarly perfect deductions. Thus, if we vary the quantity of a proposition’s subject (universal all versus indeterminate some) along with the quality or kind of the predication (positive versus negative), we arrive at all the possible combinations of the most basic kind of arguments.