Sri Aurobindo translates Katha Upanishad, First Cycle, First Chapter, Verses 20-22: “Nachiketas speaks: ‘This debate that there is over the man who has passed and some say “This he is not” and some that he is, that, taught by thee I would know; this is the third boon of the boons of my choosing.’ ”
“Yama speaks: ‘Even by the gods was this debated of old; for it is not easy of knowledge, since very subtle is the law of it. Another boon choose, O Nachiketas; importune me not, nor urge me; this, this abandon.’ ”
“Nachiketas speaks: ‘Even by the gods was this debated, it is sure, and thou thyself hast said that it is not easy of knowledge; never shall I find another like thee (1) to tell of it, nor is there any other boon that is its equal.’ ”
(1) “Yama is the knower and keeper of the cosmic Law through which the soul has to rise by death and life to the freedom of Immortality.”
Even the gods debate the question of whether something of the individual personality survives death. We can explore the long history of mankind wondering about this quesetion and find a vast array of different answers. Some hold that the various elements, physical, vital, mental, all dissolve into their respective energies and, while the momentum and direction carries on, there is no individual personality that identifies with it. Others have held that the individual goes into death and continues to experience as “that individual” in another world. Still others acknowledge the bodily decomposition but hold that at some time in the future there will be a resurrection of the very same body and personality and a rejoining with one’s friends and family. Some acknowledge that there is a soul, or Atman, that survives death, and while shedding the characteristics of the individual personality one has in a particular lifetime, gathers the experiences and evolves through multiple incarnations.
What is the truth of this? If anyone knows, Death will know! But Yama does not want to answer this question. We have statements of those who have had a near death experience, who have actually died, clinically, and then later returned to life. They speak of certain characteristic experiences and generally come back with faith. Doctors will dissect their experience and tell them that these are just the physiological symptoms of incipient brain death and that none of it is real. The debate goes on.
The answer is complex and consists not just of a philosophical statement, but a wide-ranging review, followed by a teaching which provides a roadmap for the seeker to attain wisdom through his own growth and experience, what one might call a Yogic discipline. Multiple views are explored as Death acts as the guide to the hidden deeper meaning of life and death.
Sri Aurobindo, The Upanishads, Katha Upanishad, pp. 213-241, and Kapali Sastry, Lights on the Upanishads, pp. 104-129