There is an interesting tale in the Mahabharata when the preceptor Drona was teaching the sons of Dhristarashtra and Pandu, the royal princes of the kingdom, the lesson of the day, which was “not to become angry”. He asked each of the princes if they had learned the lesson and each one dutifully responded “yes, not to become angry.”. Until he reached the eldest, the crown prince and heir to the throne, Yudhishthira, who indicated that he had not learned the lesson. The next day, and that following, the same lesson was repeated, with the same responses. Dronacharya was not used to such stubbornness, and, in a fit of temper he struck Yudhishthira. This was, in the rules that governed at that time, a capital offense. Yudhishthira responded, however, “I now have learned the lesson.” Instead of becoming angry with this affront, he internalized the lesson and recognised that he had the inner power and control to not become angry when provoked.
The importance of this tale is that a mental recognition of something is not actually the same as the realisation of it in the being. In the West, the well-known illustration is that one can read all the books about swimming, but until one gets in the water and masters the principles one has read about, one does not know how to swim.
Many who take up a spiritual discipline initially confuse mental conceptualization with realisation. They read a text or scripture that says that there is one universal world-consciousness, or some other principle and because they can repeat the words, they believe they “know” something about it. Eventually, as they mature in their practice and understanding, they understand that there is a vast difference between mental knowledge and spiritual realisation. This comes about when they first begin to have experiences, and eventually solid, persistent realisations that are not mental constructs but arise from a wholly other order of experience and are known in a different manner than just with the mind. They may feel a descent of a vast peace that embraces, and fills the being; they may see and feel the oneness and unity of all existence, they may in some instances have an ‘out of body’ experience and travel through what are known as astral planes, or any number of other experiences which do not fit the neat framework of their mental understanding.
Sri Aurobindo notes: “There are two classes of things that happen in yoga, realisations and experiences. Realisations are the reception in the consciousness and the establishment there of the fundamental truths of the Divine, of the Higher or Divine Nature, of the world-consciousness and the play of its forces, of one’s own self and real nature and the inner nature of things, the power of these things growing in one till they are a part of one’s inner life and existence, — as for instance, the realisation of the Divine Presence, the descent and settling of the higher Peace, Light, Force, Ananda in the consciousness, their workings there, the realisation of the divine or spiritual love, the perception of one’s own psychic being, the discovery of one’s own true mental being, true vital being, true physical being, the realisation of the overmind or the supramental consciousness, the clear perception of the relation of all these things to our present inferior nature and their action on it to change that lower nature. The list, of course, might be infinitely longer. These things also are often called experiences when they only come in flashes, snatches or rare visitations; they are spoken of as full realisations only when they become very positive or frequent or continuous or normal.”
“Experiences and descents are very good for preparation, but change of consciousness is the thing wanted — it is the proof that the experiences and descents have had an effect.”
Sri Aurobindo and the Mother, Growing Within: The Psychology of Inner Development, Chapter VII Growth of Consciousness, Inner Experiences, pg. 126