The information processing terms "content" and "address" are used to describe structural differences between the constructs of individual identity and identity in the equivalence sense. In both cases a sameness relation is established in spite of specific differences. The resulting constructs of identity are known to be involved in the achievement of "object permanence" and in the formation of classes; this essay suggests that the way in which they are arrived at is instrumental also in creating belief in an ontological reality. (MS)