Equality is an extremely useful relation: once we know that \(a=b\) , we can draw a great deal of important conclusions. However, it is rarely possible to conclude logically that, indeed, \(a=b\) . In this essay I discuss the notion of sameness by default: that it is sometimes beneficial to assume that two individuals are the same unless proved to be different. I demonstrate how an informal and rather procedural presentation of the idea turned, under the supervision of, and later, in collaboration with Prof. János Makowsky, into two rigorously formalized relations with important theoretical and applied implications.