After having argued that impressions-only is a theory which can explain our everyday experience, Vasubandhu then appeals to - since we do not need the concept of external objects to explain reality, then we can do away with those superfluous concepts altogether as they are most likely just mentally superimposed on our concepts of reality by the mind. Inter-subjective reality for Vasubandhu is then the causal interaction between various mental streams and their karma, and does not include any external physical objects. The soteriological importance of this theory is that, by removing the concept of an external world, it also weakens the 'internal' sense of self as observer which is supposed to be separate from the external world. To dissolve the dualism of inner and outer is also to dissolve the sense of self and other. The later Yogacara commentator Sthiramati explains this thus:"There is a grasper if there is something to be grasped, but not in the absence of what is to be grasped. Where there is no thing to be grasped, the absence of a grasper also follows, there is not just the absence of the thing to be grasped. Thus there arises the extra-mundane non-conceptual cognition that is alike without object and without cognizer."Vasubandhu also attacked the realist theories of Buddhist atomism and the Abhidharma theory of svabhava. He argued that atoms as conceived by the atomists (un-divisible entities) would not be able to come together to form larger aggregate entities, and hence that they were illogical concepts.