Formal Bennettian systems are defined around and focus on the idea of logical or qualitative complexity rather than quantitative complexity. There is thus a possible analogy to the philosophical program of logical atomism. ("Quantitative complexity", as contrasted with "qualitative", results from the presence in a practical setting of two or more actual components of the same qualitative type. However, in practical Systematics, the quantity or amount of a component also has concrete qualitative effects, and the two categories cannot always be separated.)