By the test of reason I mean logic or, to be more specific, the law of non-contradiction. Since most of chapter 8 is devoted to an analysis of this test, I can be brief. Attempts to define the law of noncontradiction seldom induce much in the way of excitement, but I offer a definition anyway. The law of noncontradiction states that A, which can stand for anything, cannot be both B and non-B at the same time in the same sense. For example, a proposition cannot be true and false