When you dream of an elephant, does an elephant appear to your mind? Indeed it appears very clearly. Is there an elephant there? No. This appearance of an elephant in your dream is a union of appearance and emptiness. It appears, yet it does not exist – yet it appears. It is the same with all external phenomena. If we understand the example of the appearance of something in a dream, it is easier to understand how the mind appears yet does not exist, and does not exist yet appears.

-- Thrangu Rinpoche