The mind is acquired "human nature". The conscience is inherent "spiritual nature".
That we do not comprehend or accept something does not invalidate its truth.
In the spiritual search doubt is beneficial, a closed mind is not. Doubt used wisely assists enlightenment; a closed mind assists ignorance.
Mind is the Soul speaking and Conscience is the Spirit speaking.
As the mind shrinks at the will of the initiate, thought flows in to fill the spaces so created.
There are no successes and failures in life, only achievements - stepping stones.