Varuna instructs Bhrigu:
“Seek to know well that from which all beings are born, that by which they live after being born, and that towards which they move and into which they merge. That is Brahman.” (Tai. 3.1)
 A well-established principle is that, upon dissolution, an effect resolves into its cause.

In his commentary (Tai. 2.6), Shankaracharya raises the following questions:
“Does an ignorant person, after departing from this world, reach the other world, or does he not? Similarly, does a person of knowledge, after departing from this world, reach the other world, or does he not?”
He explains the difficulty as follows:
“Brahman, being the cause of space and everything else, is equally the source of both the ignorant person and the person of knowledge. Therefore, one might suspect that the ignorant person, too, reaches Brahman.”
Conversely, “if the ignorant person does not reach Brahman, even though Brahman is the common source of all, one might also doubt whether the enlightened person reaches Brahman.”

This appears to present a catch-22 situation.

Resolution                                                                                                                        The difficulty arises because the questions themselves are incorrectly framed. The concepts of reaching and not reaching are meaningful when there is a distance to be traversed or there is a difference between the seeker and the goal. Neither applies to Brahman which is the true nature of the individual.

From the standpoint of Advaita Vedanta, both the ignorant person and the enlightened person are, in their true nature, Brahman. Therefore, Brahman is not something that either of them must reach in the sense of attaining a previously absent reality.                There can be no satisfactory answer to a question based on a mistaken assumption.

The distinction between the ignorant person and the enlightened person lies not in their true nature, but in their knowledge of it. The ignorant person does not know that his or her true nature is Brahman, whereas the enlightened person knows this to be the case.

Self-knowledge does not bring about a transformation into Brahman; it removes the ignorance that conceals the ever-present truth that one has always been Brahman.

Note: Translation by Swami Gambhirananda, Eight Upanishads, Advaita Ashram