 States of affairs are, as any other formation, governed by general and necessary laws, and are independent of the individual and the contingent act of judging. These structural laws or axioms as he calls them in his Erkenntnislehre govern relations between elementary psychical formations. Stumpf distinguishes between formal axioms, which apply to any objects, and material or regional axioms which belong to specific domains of objects such as the domain of phenomenology (structural relations between phenomena) and that of psychology (structural relations between elementary psychical functions). Of particular interest to logic are the axioms of consequence (Folgerungsaxiome), which are expressed in propositions and which establish a relation between the premises and the conclusion in terms of necessary inference.