An undisturbed mind is the key...

Upanishads describes the nature of our senses through the metaphor of horses pulling a chariot. 

It says-
“Know the body as the chariot itself,
 Know the reason is the charioteer,
 And the mind indeed is the reins,
 The horses they say are the senses,
 And their paths are the objects of senses..
It continues..
“He who has not the right understanding and whose mind is never steady is not the ruler of his life, like a bad     driver with wild horses.
 But he who has right understanding and whose mind is ever steady is the ruler of his life, like a good writer   with well-trained horses”

An undisturbed mind is the key...

The western concurrence to this( some of the left wing intellectuals always look for western confirmations)

Emerson said - “ Great men are those who see that thoughts rule the world”

Milton in Paradise lost wrote - “The mind is its own place and in itself can make a heaven of hell or hell of heaven”

Shakespeare wrote - “There is nothing either good or bad except that thinking makes it so”

Clarity emerges where the mind is undisturbed.
These are embedded into our conscience.

It is said -“The voice of conscience is so delicate that it is easy to stifle it but is so clear it is impossible to mistake it”.
Conscience is the endowment that senses our congruence or disparity with correct principles and lifts us towards them- when it is in shape. 

Drdd