 According to Peirce, phenomenological considerations, i.e., considerations spelled out in the Phenomenology, show that in whatever can be experienced there are at least two distinct series of categories involved that make this experience possible. Some of them are universal, i.e., are constitutive of every phenomenon, others particular, i.e., belong to a phenomenon if looked at under a specific aspect (cf. EP 2.148) like its quantitative, qualitative, relational etc. determinations. As universal categories he identifies three which he names Firstness/Category the First/First, Secondness/Category the Second/Second, and Thirdness/Category the Third/Third respectively. He defines them thus: 