 Readers might have noted that while the principle-concretum pair seems to cover some of the terrain of the old distinction between essence and existence, it does not entirely coincide with it. Hartmann rejected those terms in favor of a more accurate distinction between Sosein (“being-such-and-such-a-way”) and Dasein as “ways of being.” Dasein and Sosein can be approximately understood as existence and determination. Both real and ideal entities have both Sosein and Dasein. Mathematical entities and values “exist” in an atemporal way, for example, and have their own determinations. While the general is a dominant category in the ideal sphere and a subordinate category in the sphere of the real, individuality is a category of the sphere of real being only. In the realm of ideal being there is no individual. Ultimately, what rigorously distinguishes the real from the ideal spheres themselves are the different “intermodal relations” of necessity, possibility, and actuality in each. In Possibility and Actuality, a book which still awaits close scrutiny by researchers, Hartmann argues for some of his most startling claims.