Do you believe that nibbāna is a vanishingly rare (and possibly supernatural ) event that leads to the permanant absence of all suffering, and means that we never again have to experience emotions and thoughts that we don't like? And which may grant special psychic powers and abilities, and post-nibbāna, that we are enlightened beings and unable to behave badly? Do you also share in the taboo about discussing meditation experiences such as nibbāna?
Then you are not alone. These are common Buddhist beliefs.
Alternatively, however, we could consider nibbāna to be a natural feature of our neurophysiology and although not common, not especially rare either. In this naturalistic worldview, given the right conditions, nibbāna will be experienced; and sometimes the right conditions might be the unexpected outcome of pathology.
If you have not yet seen Jill Bolte-Taylor on TED, then please have a look. Jill's book about her experience is also fascinating as she describes how a stroke precipitated her into an experience of nibbāna (nirvana in sanskrit). Jill does not quite make the claim that she experienced nibbāna, but her description sounds right. (And see here).
What Jill's example shows is that this experience is built into our neurophysiology; it is a natural, if unusual, experience that can spontaneously appear when normal mind chatter ceases.
Jill Bolte-Taylor suffered a stroke in her left hemisphere - where language and thinking are usually performed. Normal discriminatory thinking in the left hemisphere inhibits the right hemisphere - the so called 'silent hemisphere' - where strategic assesment, holistic and pattern recognition are normally located.
Perhaps some of the profound experiences described as near death experiences (NDE's) are also induced experiences of nibbāna. Oxygen depletion disrupts the normal functioning of the brain and may shut down the sense of self partially or completely for a brief period allowing nibbāna to manifest.
Nibbāna is not simply equivalant to enlightenment. Enlightenment is a construct used to position and interpret the nibbāna experience. Depending on the particular form of Buddhism one uses, it will have its own enlightenment schema. In early Buddhism nibbāna is regarded as an experience of stream entry which can then be followed by three other levels of attainment, the highest of which is arahantship or full enlightenment. In Zen Buddhism, sartori probably equates to nibbāna . In Mahāyāna traditions there are different levels of enlightenment of which nibbāna is one.
Although the profound letting go of self that occurs in nibbāna does automatically generate great ease and pleasure and enables one to appreciate how suffering is caused and to feel deep compassion for all of us struggling in self-based thinking, the experience itself does not guarantee that one will behave well or that one is constrained in how one acts.
Existing habits will be weakened because the self is no longer centre stage, but will still exist. We will no longer feel entirely at home with previous habits and behaviours and be able to see them from a clear perspective. But nibbāna does not erase the momentum from previously learned behaviours.
This is why character training is always required. None of us can avoid careful reflection on the quality of our behaviour. If we have already developed compassionate and virtuous behavior patterns prior to nibbāna, and this may well be the case especially in a Western cultural context, then we can make good progress to enlightenment - at least as defined according to the early Buddhist Pali schema.
Nibbāna (or enlightenment) does not mean that one no longer has to operate in the world and deal with the same kinds of problems as everyone else. Or that one automatically has magical powers. It simply means that the suffering and delusion linked with believing in thought, its constructs and the self no longer occurs leaving one free to choose the best (for all) actions (most of the time).
That nibbāna does not grant omniscience is clear even in the Pali Canon - the earliest Buddhist scriptures - where the Buddha makes mistakes (such as gving a teaching that leads several monks to commit suicide). And of course the Buddha is regarded as a special being who has not only experienced nibbāna but is fully trained in virtue and concentration and perfected according to the Pali schema.
Enlightenment schemas vary. Pali and Theravada schemas are based on stepping away from an engaged life in the world and becoming a renunciant bhikkhu. There is a text that suggests that if a lay-person becomes fully enlightened then they must become a monk or die. But this is rather circuitous (and self-serving) reasoning since Pali enlightenment is defined so that it cannot really be achieved unless one is a bhikkhu (or bhikkhuni)
However, there is no natural (or supernatural) imperative that forces someone who has experienced nibbāna to disengage from an active life with family and work. In fact this is what informs the mahāyāna enlightenment schemas that encourage the bodhisattva path - an engaged path for the benefit of all sentient beings.
If we now see nibbāna as a natural and powerful potential of our neurophysiology that allows us to see beyond 'self' and that can be given meaning in different ways - in different schemas - and embedded in different cultural contexts, then we are free to create our own meaning and life path in our contemporary context that is altruistic, engaged and fully at home with the scientific worldview and evolutionary perspective.
And maybe if we move away from a religious view of nibbāna to a secular view, we can speak about it, study it, and cease to treat those who say they experience it as either saints to be worshipped or imposters to be dismissed. They might just be telling us in an objective way what they have experienced.