For this proof of principle study, we developed a scoring function that quantifies the agreement of a chemical perception tree proposed in the course of MC sampling with the chemical perception assignments associated with an existing, operational force field. This scoring function compares how the working types categorize atom and fragments, with reference types from the existing force field. Our basic problem here is to determine which of our working types best corresponds to which reference type when applied to the same set of molecules. Here, in explaining the scoring function, we focus on atom types, but the same approach is also used for other fragment types arising from direct chemical perception, as considered at the end of this subsection.