This is thus the catallel transformation (that is a transformation of one entity into an ontological duality) of quid est (what is it?) with respect to Substance (as a result of which a given Substance becomes questionable) : forma totius and forma partis (as alleles), or, perhaps better : forma partis and the rest of the forma totius. See Part II, VIA QUAESTIONES, (at the end of) f. .