These are really different facets of the same rookie and have to do with the role he can play in various relations -- each facet can come from a different proto

These are really different facets of the same rookie and have to do with the role he can play in various relations -- each facet can come from a different prototype (or class...) if necessary. So "viewed as a" or "in the role of" a Catcher, we "see" certain attributes, and "as a runner" we see others. Certain knowledge representation schemes (frame systems, description logics, default reasoning and truth-maintenance schemes, etc.) can deal with this context-sensitivity well -- programming languages tend to have some weakened notion of these things, such as Inferfaces or Traits.