A Gnani will neither talk too volubly like shallow persons nor keep complete silence.

A Gnani will neither talk too volubly like shallow persons nor keep complete silence.  He will talk as much as is necessary but no more.

Silence  really means keep quiet in controversial discussions because one  do not know what anyone has in his mind and without semantic analysis it is all useless, so silence is better.

In pursuit of truth silence means thinking constantly of the formless as against universe. Word and thought always imply duality, the object, whereas the subject, formless witness or consciousness is beyond both word and thought.

The physical silence practiced by yogis, is a sign of their ignorance, because they are thinking of tongue and lips, i.e. body and not of the formless witness, which consciousness. However it is useful to those who are not seeking truth as a discipline. Yogic silence was intended only for the ignorant, who are unfit for path of wisdom.

Consciousness is wrapped in the meaning of words. Semantics aim at clarifying meanings but AUM ultimately shows you that all words are futile because they cannot express the ultimate nature of anything: Silence alone does this. 

There is no need to renounce the worldly life and take sanyasa or monkhood in order to acquire Self-knowledge or Brahma Gnana or Atma Gnana the practical life is nothing to do with the innermost self. One must lead normal lives, striving for excellence in his practical life and inwardly strive to acquire Self-Knowledge or Brahma Gnana or Atma Gnana. Never mix up both and trying to realize the ultimate truth or Brahman because when one realizes the truth the form, time and space are mere illusion. That is the practical life within the practical world is mere illusion.  

As one advances within through perfect understanding, assimilating the Self-Knowledge or Brahma Gnana or Atma Gnana and beholds truth within him, he realizes the waking experience is illusory play. 

Formless soul Consciousness is the witness that experiences the action, the actor, and the world of separate things. It is like a light that illuminates everything in a theatre, revealing the master of ceremonies, the guests, and the dancers with complete impartiality. Even when they all depart, the light shines to reveal their absence.

What is not consciousness (formless) in the experience of diversity (waking)?  The waking and the dream cease to exist without consciousness.  The seeker, seeking and his destination   all are one in essence.

Shankara's commentary:-

Page 489: "The knower of Brahman wears no signs.  Page 500 asks in effect "Tell us what you know, show it, and let us examine it under the mental microscope." It means we must bring notions and beliefs out of vagueness into clearness. It also criticizes the mystics who claim superior knowledge but who cannot communicate it for purposes of verification.

On page 482: On Gnani: "The knower of Brahman wears no signs. Gives up the insignia of a monk's life,…his signs are not manifest, nor his behavior." 

 

A Gnani tries to lead the seeker of whatever level, to the goal of the true existence.  A Gnani will not deliver public lectures or indulge in public debate for propagating the non-dual truth like religious guru and yogis; people can only lecture for giving out falsehood, the illusions that appeal to the taste of the audience. A crowd in the public place  will contain men of varying capacities to understand, of whom only one or two might be seekers for truth or ripe for truth.