 How do we acquire moral and axiological knowledge? Ross holds ‘both in mathematics and in ethics we have certain crystal-clear intuitions from which we build up all that we can know about the nature of numbers and the nature of duty’ (FE 144). Our knowledge of the basic moral and axiological propositions which are the object of moral intuitions is non-inferential (OJ 121, 123; RG 29, 146; FE 144, 172, 262, 320). They are non-inferentially knowable because they are self-evident or knowable on the basis of an understanding of the self-evident proposition alone (RG 20n1, 29; FE 320). For example, that we have a responsibility to keep our promises is self-evident (RG 29). It is by a process of reflection on this proposition that we come to apprehend we have this responsibility. Ross thinks we can trust our moral apprehensions, and since apprehension is a matter of knowledge, and knowledge implies certainty, he is certain we have the above responsibilities and that certain things are intrinsically valuable (RG 146, 29, 30; KT 42; Skelton 2007; cf. Audi 2004).