Understanding the qualities of the mind is essential to mahamudra practice, a kind of meditation that points to the emptiness of all phenomena.
When we meditate, we wonder: what is the mind? What is consciousness, or awareness? In some ways the mind may seem unreal. It is not something tangible. The mind is not composed of the physical elements of earth, water, fire, or wind. But if the mind is not tangibly real, how is it that we are able to think and feel and do all the things that we do each day?
In Buddhist texts, the reflection of the moon on a lake is used as a metaphor to explain how things do not exist in the way that they appear to us. While they appear to be fully real, substantially existent, and to possess some intrinsic nature of their own, they do not in fact exist in that way. This analogy can help us begin to understand the way that the mind exists.
The essence of the mind is empty. We cannot see the mind, we cannot touch the mind. But to say that the mind is empty does not mean that the mind is vacuous like space. It is not empty like a void or a vacant room. It is also not devoid of characteristics. Your mind is aware. It has the quality of knowing. The nature of mind is luminosity, which allows for the dawning of appearances. These appearances can come in a variety of forms. Certain forms are consistent with the experience of samsara and certain forms are consistent with the experience of nirvana. Everything that we could experience in samsara or nirvana is a creation of the mind. And all the appearances of the mind are spontaneous. In this way the mind is also described as spontaneous.
Understanding these qualities of the mind—its essence, nature, and characteristics—are fundamental to the features of mahamudra practice. For example, in mahamudra practice, you may encounter the instruction to not abandon thoughts. This might sound very strange to meditators from other traditions, but if you really understand the nature of the mind, then you will understand the profundity of this instruction. Thoughts are not harmful things in and of themselves. The final goal of mahamudra practice is not the cessation of all thoughts. This is not something that we strive for. It is said in the mahamudra tradition that the essence of thought is the dharmakaya, the truth body of a buddha. So, in a certain sense, practicing with the aim to abandon thought would be like aiming to abandon the dharmakaya. In fact, many mahamudra masters say that when thoughts arise, they feel so happy and joyful because, for them, more thoughts mean more opportunities to experience the dharmakaya.
With this practice, you are encouraged to investigate your thoughts. The idea is that by rubbing the two sticks of thought together—using thought to look at thought—the fire of insight will ignite seemingly from nowhere. Insight does not, of course, actually arise from nowhere. Just as with fuel and fire, there is an intimate connection between thoughts and the dharmakaya, which makes it possible to find the dharmakaya present within thoughts, using the help of the tools of mindfulness and awareness.