It is clear that an Upanisadic passage such as this does not merely want to make a theoretical point (e.g. that the ātman is essentially identical with the Brahman). Its author desires to express what I have called a ‘self-authenticating experience’. Beyond all rational analysis, the experience carries its own validity, ‘conviction’. The world is made sense of not by means of mythical images, correlational constructions, or quasi-scientific analysis, but through a different mode. Let us call it, temporarily, ‘mystical’.

But what do we mean by ‘mystical’? Within the Christian tradition, the word appears to refer to experiences which are granted to a few select and saintly individuals and which simply happen to them. Not so in ancient India. There such experiences are understood to lie within the potential of every human being, provided he knows how to go about it. Let us first look at a passage in which the continuity with other forms of experiencing the world is suggested.