In the place [the core of our being] where 'I' [our mind or individual self] merges [or becomes one], the one [true knowledge] appears [or shines forth] spontaneously [or as ourself] as 'I [am] I'. That itself [or that, which is ourself] is the whole [the infinite totality or fullness of being, consciousness and happiness].On pages 312 to 314 of the present e-book version I discuss the meaning of verse 21, and I conclude my explanation with the following paragraph:
That [one infinite whole that shines thus as 'I am I'] is at all times [in the past, present and future, and in all eternity] the [true] import of the word 'I', because of the absence of our non-existence even in sleep, which is devoid of [any separate or finite sense of] 'I'.
Therefore, since it is not limited in any way by any finite adjuncts, or by any finite dimensions such as time or space, our essential consciousness of being, which we always experience as 'I am', is eternal and infinite. Since it is not limited as 'this' or 'that', it is not separate from anything. Since we always experience it as the base of all our knowledge of everything, it is in fact the true essence of all things. Since it alone endures through and beyond all time, while all other forms of knowledge appear and disappear within time, it is the only knowledge that is absolutely true.While revising Happiness and the Art of Being in preparation for its forthcoming publication in print, I have added the following after this paragraph:
All other forms of knowledge appear and disappear because they are known only by our mind, which itself appears and disappears. Since it appears only in waking and dream, and disappears in sleep, our mind cannot be our real self — the true import of the word 'I'. Therefore in verse 717 of Guru Vachaka Kovai Sri Ramana says:
Since the body-soul [the embodied soul, the finite consciousness that imagines itself to be a body] itself appears and disappears, [it cannot be the enduring reality denoted by the word 'I', and hence] atma [our real self], which is the abiding base of the body-soul, alone is the correct [direct or honest] porul [import, significance or reality] of the word that [each embodied soul] says as 'I'. Know that when [we] scrutinise, [we will discover only our own atma or fundamental self-consciousness] to be the conclusive porul [the ultimate reality denoted by the word 'I'].The basic reality that underlies the imaginary appearance and disappearance of our body-bound mind is only our own essential self-conscious being, which we always experience as 'I am'. Though everything else appears and disappears, our basic self-consciousness neither appears nor disappears, because it endures in all states and at all times, and hence it alone is the reality that is truly denoted when we say the word 'I'.
[For another discussion of this same subject, please refer to my earlier post The true import of 'I am'.]