" But beyond the mind, beyond our thoughts, there is something we call the 'nature of the mind', the mind's true condition, which is beyond all limits. If it is beyond the mind, though, how can we approach an understanding of it?

Let's take the example of a mirror. When we look into a mirror we see in it the reflected images of any objects that are in front of it; we don't see the nature of the mirror. But what do we mean by this 'nature of the mirror'? We mean its capacity to reflect, definable as its clarity, its purity, and its limpidity, which are indispensable conditions for the manifestation of reflections. This 'nature of the mirror' is not something visible, and the only way we can conceive of it is through the images reflected in the mirror. In the same way, we only know and have concrete experience of that which is relative to our condition of body, voice, and mind. But this itself is the way to understand their true nature. "

― Namkhai Norbu , Dzogchen: The Self-Perfected State