They could not be atomic combinations because we cannot affirm if such combinations are one with atoms or separate therefrom. According to the Vijnanavadins or the Yogachara system the Vijnana Skandha or idea alone is real. An object like pot or chair which is perceived outside is nothing more than ideas. The Vijnana or idea modifies itself into the form of an object. All worldly activities can go on with mere ideas, just as in dream all activities are performed with the thought objects.
Ideas only exist.
It is useless to assume that the object is something different from the idea. It is possible to have practical thought and intercourse without external objects, just as it is done in dream. All practical purposes are well rendered possible by admitting the reality of ideas only, because no good purpose is served by additional assumption of external objects corresponding to internal ideas. The mind assumes different shapes owing to the different Vasanas or desire-impressions submerged in it. Just as these Vasanas create the dream world, so the external world in the waking state is also the result of Vasanas.