The differences of a person in knowledge and a person who is not ; is that the person in knowledge has acquired Jnana , buddhi yoga , the yoga of intelligence.
This knowledge is brought about in various ways and generally through many lives .
It is recommended that a person who is inhabited by a ghost , needs to engage himself in purificatory processes of various actions , and after acting correctly like an ordinary man should do , he will regain knowledge of who he is , ie . He is a man, not a ghost .
By repeatedly telling the man he is not a ghost won’t do ,the ghost will overpower him . He must engage in purificatory actions to revive his true position.
Karma yoga, as in Niskarma karma yoga, leads to knowledge of God and knowledge of ones true self as an associate of God . The process of jnana alone is not suitable for 99.9 % of people but  by Niskarma karma yoga, one automatically aquires knowledge by working correctly and realises  the source of  all energies within and outside the body . Also, how best they can be  employed for the benefit of an individual and everyone else . An offering of energy  back to the energetic source.  By Niskarma karm,  one soon realises the futility of temporary action in matter , and a realisation comes about of dualism and consciousness and  its origins .Jnana or buddhi yoga is the result of pure actions. Automatically reviving pure knowledge of a person who is artificially trying to enjoy matter.  The inner consciousness is not made of matter , so matter will never satisfy consciousness.  The ghost like illusion of being something one is not is cleared up by Niskarma karma yoga leading to pure Jnana .  Then, pure Bhakti, the yoga of pure devotional service can be understood, which reveals one’s spiritual form in relation to God
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