 Stein defines ontology as the science of the “basic forms of being and of beings” (2000c: 161[182]). In agreement with Aquinas and Husserl, she holds that ontological concepts can be discovered by “logical reasoning” (1931: 17[22]). She begins from Husserl’s distinction between formal and material ontologies. Formal ontology, for Stein, considers being simply as ”being”, that which is. Thus it arrives at the formal notion of “something that is” or just “something” (1931: 22[28]). Formal ontology, for Stein, following Husserl, studies formal principles such as “act”, “potency”, “object”, “individual”, and so on. Formal ontology identifies a priori conceptual truths such as: “only a perfectly simple whole can be absolutely actual” (1931: 38[52]). Stein identifies three fundamental ontological forms: “object” (Gegenstand), “what” (Was), and “being” (Sein; 1931: 99[147]). Stein distinguishes between the species and the concrete individual. Individual entities have “thisness” or haeccitas (1931: 29[39]). Invoking Dun Scotus, Stein speaks of haeccitas, and of “individual essence” (Einzelwesen; 1950/2006: 79[81]), a concept she also finds in Husserl. Paradoxically, there is an essence that is responsible for something being an individual, a particular “this”. Things have a “possibility of essence” (Wesensmöglichkeit, Stein 1950/2006: 80[83]), the capacity to actualize their nature. For Stein, from consideration of one’s own being and non-being, one can grasp the notion of actuality and possibility and then argue for the possibility of full actuality as is found in divine being.