Taxonomy is Gray
From the time of Plato, philosophers have been outlining the world as they saw it and they truly built an outline; they truly built a taxonomy of the world as they saw it. The way we perceive some field, or reality in general, is our own philosophy. If we look at the world through these lenses we see it one way; we look at the world through a different set of lenses, we see it absolutely differently. That is important to realize when building a thesaurus, because people are thinking of a field in one specific way or another.