Every discussion which is made from an egoistic standpoint is corrupted from the start and cannot yield an absolutely sure conclusion. The ego puts its own interest first and twists every argument, word, even fact to suit that interest.
The ego will always be able to find ways to keep the aspirant busy in self-improvement, thus binding him or her to the fact that the self is still there behind all the improvements. For why should the ego kill itself?
Whoever wants the "I" to yield up its mysterious and tremendous secret must stop it from looking perpetually in the mirror, must stop the little ego's fascination with its own image.