Oral records of their discoveries began to be collected around 1000 B.C. or even earlier, in fragments called the Upanishads. Individualistic in their expression, yet completely universal, these ecstatic documents belong to no particular religion but to all mankind. They are not systematic philosophy; they are not philosophy at all. Each Upanishad contains the record of a darshana: literally something seen, a view not of the world of everyday experience but of the deep, still realms beneath the sense-world, accessible in deep meditation:
