Introspection, or 'sitting in the silence,' is an unscientific way of trying to force apart the mind and senses, tied together by the life force. The contemplative mind, attempting its return to divinity, is constantly dragged back toward the senses by the life currents.
Carrying a thought with dynamic will power means holding it until that thought pattern develops dynamic force. When a thought is made dynamic by will force, it can manifest according to the mental blueprint you have created.
The yogi should meditate on a firm seat, one that is clean - untainted by dirt or unspiritual vibrations of others. The thought or life force emanating from an individual saturates the objects he uses and his dwelling.
Medicine has its limitations, Life Force has none.
There are always two forces warring against each other within us.