Buddhism, and especially Tibetan or Vajrayana Buddhism, is all about seeing the true nature of our mind, taming and transforming this wild mind. A frequently used analogy as to the true nature of mind (and there are MANY such analogies) is that of the mind as a vase. If we look at a vase we generally consider there is an inside of a vase and an outside of the vase. However, if we shatter the vase we quickly realize the space inside is actually continuous with the space outside the vase, there never was a separation between the two to begin with. It was a mistaken perception. This is an example of the duality / non-duality concept in buddhism.