Enlightenment in a secular context often means the "full comprehension of a situation", but in spiritual terms the word alludes to a spiritual revelation or deep insight into the meaning and purpose of all things, communication with or understanding of the mind of God, profound spiritual understanding or a fundamentally changed consciousness whereby everything is perceived as a unity.
Some scientists believe that during meditative states leading up to the subjective experience of enlightenment there are actual physical changes in the brain. wikip

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