 These philosophers do however disagree about substantive matters. In particular, Reid lists as the first principle of common sense: “The operations of our minds are attended with consciousness; and this consciousness is the evidence, the only evidence which we have or can have of their existence” (Reid [EIP], p. 41). Campbell on the other hand lists three sorts of intuitive evidence. The first concerns our unmediated insight into the truth of mathematical axioms and the third concerns common sense principles. The second concerns the deliverances of consciousness, consciousness being the faculty through which we learn directly of the occurrence of mental acts — thinking, remembering, being in pain, and so on. What is listed as a principle of common sense by Reid is, therefore, according to Campbell, to be contrasted with such principles. Aside from this, however, it is clear that Campbell is philosophically very close to Reid, even if Reid is unquestionably the greater philosopher.