Key terms in Buddhism are not all that self-explanatory. Few are, if any. Least of all is ‘enlightenment’ or ‘nirvana’ self-explanatory. Making the matter of explanation even more difficult nirvana or realizing the unconditioned is not a sensory experience. Much less being something shared with others. But this is not the end of our travails.
Most importantly we cannot realize nirvana with pre-loaded suppositions or assumptions about what Buddhism is. We have to attain the very same insight that Siddhartha did long ago. We first have to purify our minds. This is the extremely difficult part of Buddhism because most of practitioners never end up fully purifying their minds to be adequate with Siddhartha’s mind when he awakened.
They imagine they have adequately purified their minds but that is all delusional thinking. Only when the practitioner exhausts all of their presuppositions are they considered purified. So when does this happen? Not when a practitioner expects or believes it is so. After awakening, only then does the practitioner realize that he or she had come to the end of their wits.
This is another one of those Zen mysteries that is difficult to explain with conventional words. Everything in our life it’s like a dream or it is like being in a play in which we have forgotten who we actually are. And all the people that we know in the play are in the same boat as we are. They have over-identified with their character, so much so, they have forgotten who they are, too.
Another odd way of putting it, we are like appliances who have no idea what electricity is. All the appliances have identified themselves with what they do such as opening cans, or washing clothes or vacuuming. The term ‘electricity’ like the Buddhist notion of spirit or Mind (G., Geist) is a complete and unfathomable mystery.