You must go beyond them into what is undefinable and indescribable, except in negative terms

Q: How do I come to know that my experience is universal?
M: At the end of your meditation all is known directly, no proofs whatsoever are required. Just as every drop of the ocean carries the taste of the ocean, so does every moment carry the taste of eternity. Definitions and descriptions have their place as useful incentives for further search, but you must go beyond them into what is undefinable and indescribable, except in negative terms.
After all, even universality and eternity are mere concepts, the opposites of being place and time-bound. Reality is not a concept, nor the manifestation of a concept. It has nothing to do with concepts. Concern yourself with your mind, remove its distortions and impurities. Once you had the taste of your own self, you will find it everywhere and at all times. Therefore, it is so important that
you should come to it. Once you know it, you will never lose it. But you must give yourself the opportunity through intensive, even arduous meditation.