The same goes with any mental concept--- manifest vs unmanifest, sensory and non-sensory experience, etc. It is like trying to draw a line on the air or the water--- there is no stable basis for line drawing or boundary making.
Sherab wrote: The whole point of the teachings on emptiness is to teach us that there is no point in clinging to any phenomena, be that a person and relationship with that person, an object considered valuable in a particular society, a powerful position in society, etc. In short, the experience of any or all phenomena is not to be relied upon. Phenomena are what is experienced via the senses, including the mental sense. What one should strive for and rely upon is direct knowledge, a knowledge not mediated via any of the senses, a non-dual knowledge.