 Ross’s conception of self-evidence is stronger than the standard understanding because he held self-evident propositions are certain. In the passage quoted, Ross does not explicitly claim that self-evident propositions are certain, but he suggests they are when he claims that self-evident moral propositions are like mathematical axioms and logical truths. And two paragraphs later he explicitly claims that our judgments regarding prima facie duties are certain. (SE) asserts only that self-evident propositions are evident, not that they are certain.