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. XII The wise, who by means of the highest meditation on the Self knows the Ancient One, difficult to perceive, seated in the innermost recess, hidden in the cave of the heart, dwelling in the depth of inner being, (he who knows that One) as God, is liberated from the fetters of joy and sorrow. XIII A mortal, having heard and fully grasped this, and having realized through discrimination the subtle Self, rejoices, because he has obtained that which is the source of all joy. I think the abode (of Truth) is open to Nachiketas. The Scriptures give three stages in all spiritual attainment. The aspirant must first hear about the Truth from an enlightened teacher; next he must reflect upon what he has heard; then by constant practice of discrimination and meditation he realizes it; and with realization comes the fulfilment of every desire, because it unites him with the source of all. Having beheld this, a man learns that all sense pleasures are but fragmentary reflections of that one supreme joy, which can be found in the true Self alone. Yama assures Nachiketas that there is no doubt of his realizing the Truth, because he has shown the highest discrimination as well as fixity of purpose. XIV Nachiketas said: That which thou seest, which is neither virtue nor vice, neither cause nor effect, neither past nor future (but beyond these), tell me That. XV Yama replied: That goal which all the Vedas glorify, which all austerities proclaim, desiring which (people) practice Brahmacharya (a life of continence and service), that goal I tell thee briefly--it is Aum.