Material Entity

In CRO, Material entities include material objects, cavities (Spaces), aggregations and any fiat locations, including points, boundaries and surfaces defined on such entities. The taxonomy is shown below.

One detail in BFO that causes repeated difficulty in its axiomatisation is the treatment of Spatial Region as a sibling of Site and Continuant fiat boundary, under Immaterial entity. The problem is that although Site and Continuant fiat boundary are physically immaterial, they are materially dependent, since they are created only by the presence of Material entities (Object, etc).

Spatial regions in BFO on the other hand have no material or causal dependence at all, since they describe spatial reference frames independent of objects.

In healthcare data, we need a cleaner treatment of material objects and their causally dependent spaces and boundaries. For this reason, the SPLASH RM taxonomy adjusts BFO by adding a new Materially dependent entity category below Independent continuant.