Nirvana is a state void of defilements, ignorance, craving, clinging and void of all conditioned things. Thus, Nirvana is called supremely void (Paramam Suññam) or the highest void (Aggasuññam). It is void of false self concept and all that pertains to false self concept. In a living enlightened one (Saupadisesanibbanadhatu) still possessing the Five Aggregates, it is being unfettered from mundane causes and conditions. This is called the void of highest benefit. No Five Aggregates remains for Lord Buddha, Private Buddhas and Arahants (Asekhamuni). They have let go of the Five Aggregates and attained the Nirvana Element (Nibbanadhatu). The Nirvana Element is eternal without birth, aging, pain and death. It is everlasting, supreme, happiness, stable and firm.
Even at the death of an Asekhamuni, the Nirvana Element, which supports the state of Nirvana, does not become extinguished. This is described in the simile of an empty house or empty pot. If the house or the pot is empty, it does not mean that there is no house or no pot. It means that the house or the pot is empty of other things.
By the word void or empty, Lord Buddha does not mean that ultimate dhamma does not exist, only that it is without the essence of self [worldly designated self, i.e. a doer or a feeler]. As the Venerable Mahanama Thera states:
The words empty of self and things belonging to self mean void of self that the world designates as “doer, feeler, or possessor of own power” and of articles of self, because there is no such self. The eyes etc. are all of the nature of the world. The eye is called “of the world” because of its perishability. Moreover, because there is no self or things belonging to self in the world, therefore, it is said “the world is void.” Even Supra-mundane dhammas are empty of self and that belonging to self. Here, the Venerable refers only to mundane dhammas to suit the question asked.
By the word “empty,” the Venerable does not mean that “there is no dhamma,” but refers to the lack of essence in self and things belonging to self. When it is said in the world that “the house is empty, the pot is empty,” it does not mean that there is no house and no pot, but means that there are no other things in the house and the pot.
Lord Buddha also states, “That which is not there is empty of it. But, in regard to what remains there he comprehends, ‘That being, this is.”
(Kh. A. 278-279).