Q: At the end of the day, what does knowledge of self give us ? It does not help to answer the burning question of why the appearance/dream/mAyA that we are experiencing as humans or animals exists. Also, it appears that even if one attains knowledge of self in one life, he/she can actually become a cockroach in the next due to karmic effect, ie we are not really liberated from the brith-death cycle. The only benefit I do see in a life in which one attains knowledge of self is that one might lead a life devoid of misery in the mind as we sail through good and bad times, even though we may experience physical pain.
A (Dennis): Self-knowledge removes Self-ignorance and it is that which makes us think we are limited, unhappy, doomed to old age and death. With Self-knowledge we realize that we are not human, living in an inhospitable world; we are brahman. The world appears as separate because of our ignorance. On gaining Self-knowledge, we realize that it’s substance is nothing but brahman.
From the perspective of the ignorant person, there is rebirth (possibly as a cockroach) and we are subject to karma. With Self-knowledge, we realize that there is no person, no birth or rebirth, no death, no creation.
The idea that knowledge is pointless is actually the main argument of the pUrvamImAMsika philosopher. They believe that only the karmakANDa portion of the Vedas is relevant – rituals that we have to perform in order to gain benefits. They say that the Upanishads etc are only supporting material to be meditated on. In the Brahmasutras, I.1.4, Vyasa effectively refutes all those philosophers who deny that brahman is the principal topic of the Vedas. But he does this with the single word ‘tu’ (tattu samanvayAt). Fortunately Shankara takes the opportunity to take up arms against pUrvamImAMsA. Whilst he agrees that knowledge in itself is often useless – we need actually to do something in order to gain some benefit – there is one situation in which ONLY knowledge bears fruit. That is when the problem is one of ignorance. The classic example is the rope mistaken for a snake. As soon as we find out that it is a rope, all our fears etc disappear. And our essential problem in life is that we believe we are a limited person. The knowledge that is to be gained from Advaita is that we are brahman – and that reveals that we have no real problems at all.