One of the Six Yogas of Naropa is Yoga of Clear Light. In this yoga the essence of mind is defined as “Clear Light”. The Clear Light appears openly in three states: in deep sleep, after death and samadhi.
Duality is a tendency of mind to see itself as an essence different from Clear Light. A mind that has overcome duality is able to recognize itself as Clear Light.
The following Mudra of Clear Light is overcoming duality:
– The little finger symbolizes Clear Light in deep sleep
– The thumb symbolizes Clear Light after death
– The middle finger symbolizes Clear Light in samadhi
– The two upright fingers overcome duality