There are citta, cetasika, rupa, and nibbana as ultimate realities.
No other things are realities. Only these four are real in their ultimate sense and they are always true at any given time and
at anywhere. In the previous pages, citta, cetasika, and rupa have been discussed in some detail. There is a fourth ultimate
realities. It is nibbana. Nibbana the term derives from
nivana or nirvana. Ni means nikkhanta or liberated from vana
or binding. Vana is the dhamma that bind various different lives in the samsara. So nibbana means liberated from binding in the samsara. This binding is tanha. Even though there is a single nibbana as its nature, nibbana is talked to have two different forms, saupadisesa nibbana and anupadisesa nibbana. Saupadisesa nibbana is nibbana when sattas are still in the samsara are when they are alive. This nibbana is only present in
arahats or anagams while they are in nirodha samapatti. Nirodha means disappearance and samapatti means to be in a state of. Anupadisesa nibbana is the state immediately after cuti citta of arahats. Immediately after cuti citta of arahats, there is no more kammaja rupa, cittaja rupa and
aharaja rupa. That state from the sattas just gone to nibbana is said to be the state of nibbana called anupadisesa nibbana as there is no trace of so called satta that is no citta, no cetasika, no kammaja rupa, no citta rupa, and no aharaja rupa. Utuja rupa just left is like other bahiddhika rupa and not attached to any satta. Sosuch nibbana is a complete and absolute peace. This is the state all Buddhists are trying to attain after their paccima bhava or final life . From view point of contemplation, there are three kinds of nibbana. They are sunnata nibbana, animitta nibbana, and appanihita nibbana. Sunnata nibbana means nibbana
is free of arammana for tanha to arise. There is no atta or ego in
ultimate sense. Nibbana is free of attajiva or any self or any life. So as there is free of such life, self or anything, the nibbana is called sunnata
nibbana or voided emptiness of peace. When ariya to be was contemplating on dhamma as anatta, then the nibbana that he saw when magga citta arose is called sunnata nibbana. Because as he was viewing as anatta, and as there is no atta and free of atta, then the nibbana that he saw is called sunnata nibbana. Animitta nibbana means nibbana is free of raga, kilesa and it is free of bases and causal things. When ariya to be was viewing
dhamma at magga citta, if he saw dhamma as anicca, then the nibbana that he saw is called animitta nibbana. Because there is no nicca or permanent nimitta in dhamma. So his nibbana is animitta nibbana. Appanihita nibbana means nibbana is not to be craving for as in cases of tanha, raga, kilesa,
etc etc. When ariya to be was viewing dhamma at magga citta, if he saw dhamma as dukkha or suffering then the nibbana that he saw is called appanihita nibbana. Because nibbana is free of tanha, raga, and any
defilements. Even though these are contemplated, there is only a single nibbana in terms of its character and in ultimate sense. Nibbana is an absolute peace. This peace can be understood by viewing absence of any fire or any suffering. When not in nibbana or not in the state of nibbana, then sattas will be in the domain of sankhata dhamma. This means that they all will be in loka that includes kama loka or kama realms or sensual sphere, rupa loka or rupa brahma realms or fine material sphere and arupa loka or arupa brahma realms or immaterial sphere. As long as satta are in these realms that is 31 realms, then they all will be in their samsara and they will be suffering from different kinds of suffering. These sufferings are called fires. When fires are all totally extinguished, the absence of fires in the presence of which are hot and disagreeable, will make complete peace and free of suffering. By comparison its absence can be realised as absolute peace while itspresence is hot, making restless and peaceless.
Nibbana is not rupa dhamma. It is nama dhamma. Nibbana is not a khandha or aggregate. But nibbana can be arammana or object of mind. Nibbana is dhammarammana. Nibbana can be ayatana. It is dhammayatana. Ayatana are dhamma or nature that are the cause of arising of citta by being arammana or object or by being dvara or door. Citta, cetasika, and rupa are constituted in 18 kinds of dhatu or dhamma elements. Nibbana can be dhamma dhatu. But nibbana is not sankhata dhatu as in cases of citta, cetasika, and rupa. Nibbana is asankhata dhatu. Sankhata dhatu are those whose arising and existence are influenced by one of four causes namely kamma, citta, utu, and ahara. Nibbana cannot be influenced by these four causes. Nibbana is asankhata dhatu. It is absolute peace and free of any suffering and any fire. So nibbana is what all Buddhists are intended as their destination.