When taught by a man of inferior understanding, this Atman cannot be truly known, even though frequently thought upon. There is no way (to know It) unless it is taught by another (an illumined teacher), for it is subtler than the subtle and beyond argument.
IX
O Dearest, this Atman cannot be attained by argument; It is truly known only when taught by another (a wise teacher). O Nachiketas, thou hast attained It. Thou art fixed in Truth. May we ever, find a questioner like thee.
Knowledge of the Atman or Self cannot be attained when it is taught by those who themselves lack in real understanding of It; and who therefore, having no definite conviction of their own, differ among themselves as to its nature and existence. Only he who has been able to perceive the Self directly, through the unfoldment of his higher nature, can proclaim what It actually is; and his words alone carry weight and bring illumination. It is too subtle to be reached by argument. This secret regarding the Hereafter cannot be known through reasoning or mere intellectual gymnastics. It is to be attained only in a state of consciousness which transcends the boundary line of reason.
X
I know that (earthly) treasure is transitory, for the eternal can never be attained by things which are non-eternal. Hence the Nachiketa fire (sacrifice) has been performed by me with perishable things and yet I have attained the eternal.
XI
O Nachiketas, thou hast seen the fulfillment of all desires, the basis of the universe, the endless fruit of sacrificial rites, the other shore where there is no fear, that which is praiseworthy, the great and wide support; yet, being wise, thou hast rejected all with firm resolve.
The teacher, saying that the imperishable cannot be attained by the perishable, shows that no amount of observance of rituals and ceremonies can earn the imperishable and eternal. Although the Nachiketa fire-sacrifice may bring results which seem eternal to mortals because of their long duration, yet they too must come to an end; therefore this sacrifice cannot lead to the final goal. Yama praises Nachiketas because, when all heavenly and earthly pleasures, as well as knowledge of all realms and their enjoyments were offered him, yet he cast them aside and remained firm in his desire for Truth alone.