When he stated these principles, Chisholm made use of several terms of epistemic appraisal. He appreciated the importance of explaining precisely what each of these terms means. He also appreciated the importance of explaining precisely how they are related. In an effort to explain all this, Chisholm started with a single primitive epistemic concept — this is the concept of greater reasonability, which relates the holding of one propositional attitude toward some proposition with the holding some other propositional attitude toward some proposition. In his discussion of this concept, he pointed out that holding an attitude (belief, denial, withholding) in one proposition could be more reasonable for a certain subject than holding some attitude (belief, denial, withholding) in another proposition. And then, making use of this fundamental epistemic concept (as well as the concepts of belief, refraining and negation), Chisholm defined the concepts of certainty, being evident, being beyond reasonable doubt, being acceptable, and so on.