This paper discusses the semantics and usage of rei cation as applied to relations and tuples. The rei cation of a tuple is a proposition object possessing a case role for each domain attribute in the tuple. The rei cation of a set of llers of a role is an object sometimes referred to as a \roleset". In the course of de ning rei cation mechanisms for the Loom knowledge representation system, we have unearthed several open issues that come into focus when considering equivalence relations between these kinds of rei ed objects. Another type of rei cation produces an individual that represents a view of another individual lling a particular role. We present a number of semantic variations of this rei cation operation, and argue that the unbridled application of such rei cation operators has the potential to overwhelm the representation mechanism. We suggest that a regimen that merges various similar but non-equivalent classes of individuals might be preferable to a system that insists on unique representations for each possible abstraction of an individual.