"The fundamental innate mind of clear light (Tib. འོད་གསལ་, Wyl. ‘od gsal) is considered to be the nature of mind, or the ultimate root of consciousness, and can be understood at several levels: according to the teachings of the sutra system, in the context of the tantric teachings, and in the context of Dzogchen.
The unique feature of the Dzogchen approach is that right from the beginning you make the experience of clear light itself manifest, almost as if it were something tangible – a direct, bare experience of clear light. 
In Dzogchen, on the basis of the clear light itself, the way in which the clear light abides is made vivid and certain by the aspect of rigpa or knowing. This is free from any overlay of delusion and from any corrupting effect, due to conceptual thoughts, that will inhibit the experience of clear light. "
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