4 stage of Enlightment - Stream Enterer, Once Returner, Non Returner and the Arahat.

4 stage of Enlightment - Stream Enterer, Once Returner, Non Returner and the Arahat.

The four stages ofenlightenment in Buddhism are the four progressive stages resulting in full enlightenment as an Arahat.

These four stages are Sotapanna, Sakadagami, Anagami, and Arahat which meant the Stream Enterer, Once Returner, Non Returner and the Arahat respectively.

The Buddha referred to people who are at one of these four stages as noble people (ariya-puggala) and the community of such persons as the noble sangha (ariya-sangha).

Stream Enterer

The Stream Enterer has supposedly cut off three of ten fetters which block one from full enlightenment. These three fetters which the Stream-Winner has irreversibly removed are:

 1) identification with the five aggregates (body, feeling, perception, mental formations and consciousness) as a "self" or part of a "self" or belonging to a "self" or as a "self" somehow being part of these aggregates. (There is no self)

2) doubt about whether or not the Buddha was fully enlightened

3) belief that rites and rituals, in and of themselves, will lead to enlightenment

The Stream Enterer will:

1) Inability to be reborn in the "lower realms" (animal, ghost and hell realms). Assured of being reborn only as either a human being or a deva (heavenly being).

2) Assured of enlightenment within 7 lifetimes at most.

3) Inability to regress on the Eightfold Path to the state of "putthujana" (ordinary worldling).

Once-returner

The second stage is Sakadagami, The once-returner will at most return to the human world one more time.

Both the stream-enterer and the once-returner have abandoned the first three fetters.

The stream-enterer and once-returner are distinguished by the fact that the once-returner has weakened lust, hate, and delusion to a greater degree.

The once-returner therefore has fewer than seven rebirths. They may take place in higher planes but will include rebirth in the human world at most only once more.

Non-returner

The third stage is that of the Anagami, The non-returner, having overcome sensuality, does not return to the human world, or any unfortunate world lower than that, after death.

Instead, non-returners are reborn in one of the five special worlds called  "Pure Abodes", and there attain Enlightment - Nibbana.

An Anagami has abandoned the five lower fetters, out of ten total fetters, that bind beings to the cycle of rebirth which include the above 3 factors of Stream Enterer 1) identity view 2) doubt 3) ritual attachment and 2 other factors of 4) sensual desire 5) ill will

Arahant

The fourth stage is that of Arahant, a fully awakened person. He has abandoned all ten fetters 1) identity view 2) doubt 3) ritual attachment 4) sensual desire 5) ill will 6) material-rebirth lust 7) immaterial-rebirth lust 8) conceit 9) restlessness 10) ignorance
and, upon death will never be reborn in any plane or world.

Full Enlighted Buddha

The Buddha is not only an Arahant but also full enlighted. There are two perspectives of enlightenment 1) realization of non-self/emptiness 2) wisdom of all dharma - knowing everything. This is only fully attained by Buddha, not Arahant.

To become a Buddha, one practice as a Bodhisattva until he has perfected all virtues, then he becomes a Buddha.

Throughout this process, he not only has to eliminate his own afflictions, but also has to benefit uncountable sentient beings (to liberate).

It takes uncountable aeons to become a Buddha, accordingly to the Buddha. An Aeon is :

“An aeon is long, bhikkhu, the Blessed One said. It is more than several hundred thousand years. Suppose, bhikkhu, there was a great stone mountain a yojana long, a yojana wide, and a yojana high, without holes or crevices, one solid mass of rock. At the end of every hundred years a man would stroke it once with a piece of Kasian (very soft) cloth. That great stone mountain might by this effort be worn away and eliminated but the aeon would still have not come to an end. So long is an aeon, bhikkhu.” Samyutta Nikaya 15.5

A Private Buddha

A Pratyekabuddha or paccekabuddha "a private buddha", is one of three types of enlightened beings according to some schools of Buddhism. The other two types are arhats and sammāsambuddhas (Sanskrit samyaksambuddhas).

Pratyekabuddhas are said to achieve enlightenment on their own, without the use of teachers or guides, according to some traditions by contemplating the principle of dependent origination. They are said to arise only in ages where there is no Buddha and the Buddhist teachings