We can infer that mental experience requires sensory experience, or respectively memory of sensory experience. Sensory experience in turn requires the body. If we carried through a thought experiment and examined whether each of the skandhas is able to exist without the other four, we would find that this is not possible. The latter four aggregates all depend on the body. Without the brain and the nervous system there is no consciousness, no sensation, no perception, and no mental formations. On the other hand, we cannot imagine the body to function without the mind. The body and the mind depend on each other, the five skandhas depend on each other. We must conclude that none of the skandhas is fundamental. Body, sensations, perceptions, mental formations, and consciousness are interrelated. Experiences emerge from the interaction of all five skandhas. Just as objects, experiences are conditioned by the interplay of multiple phenomena. Experience has no inherent existence either.Our brain is advanced enough to reflect on its experiences. By means of self-reference we can direct mental activity onto itself. For example, we can think about thought. From this arises a division between subject, percept, and object. The percept is the mental impression, the subject is the owner of it, the thinker, and the object is that which causes the mental impression. This threefold division seems so natural to us that it is reflected in the grammar of most human languages. We perceive the separation of subject, percept, and object as real, because mind attributes an owner to experience and thought. This owner is the "self", the subject, the centre of consciousness, the supposed psychological entity. Surprisingly, this entity remains completely undetectable. Body, feeling, perception, and mental formations are not the self. Consciousness is not the self either, otherwise it would follow that the self temporarily ceases to exist during unconscious states, for example during deep sleep.
We might ask how "self" can be independent of a surrounding world. Is it possible for the self to exist in a mental vacuum, a world devoid of sense impressions, thought, and mental images? Would the self not literally run out of fuel if it lacked thoughts and contents to identify itself with or to set itself apart from? It seems there is no basis an independent entity. It seems more that the self is an emergent phenomenon arising from the application of complex interpretative schemes to perception. In particular, it arises from the conceptual division between subject, object, and percept. Through introspection it is possible to realise that the "self" is not fundamental. It is created by the mind through identification and discernment. The "self" is itself a mental formation - a product of mind. It is therefore empty of inherent existence.
http://thebigview.com/buddhism/emptiness.html
