Photo: Guru Rinpoche's palm print in solid rock, a demonstration for a private group of students that phenomena are empty of inherent existence and do not exist separate from mind.

There are only two branches to the teachings: emptiness and method. The Buddha taught all other teachings - all methods - in order to illuminate or to point-out the emptiness of all phenomena.

Emptiness is the prajna, the wisdom, the special insight, and the valid perception which eliminates the root of suffering, which is ignorance. Everything else within Buddhist philosophy, ethics, metaphysics, cosmology, and psychology flows out of the question: "Empty of what?"

Emptiness is revealed or recognized using a number of philosophical systems and types of analysis. This seems to be where many people's confusion arises. Within Buddhism, there are - at least - four major philosophical positions with different ideas on both the conventional and ultimate nature of reality. Within those four we find, maybe 20-30 interpretations and hundreds of methods of practice.

In other words, there is no final agreement between all Buddhists on what the Buddha meant when he said, "It's empty." This - in part - is due to the fact that (arguably) the Buddha meant different things on different occasions when speaking about emptiness. That being said, scholars and cave-dwelling yogis from the last 2,500 years of Buddhist thought have mostly identified with and fallen into these four major schools of thought with regards to emptiness:

1. Sautrantika. Conventional means things arise, exist, and cease based upon a huge set of causes and conditions. Things are composed of various parts, upon which basis they arise and exist. The "ultimate" means there is no static self to the person and sometimes also, no static self to material phenomena.

Phenomena are self-arising and have self established characteristics - including impermanence - but there is no static, unchanging self to the person. This includes most of the "Orthodox" modern Theravada schools, but the modern Theravada is a very diverse tradition.

2. Chittamatra or Yogacara. This school literally translates as "mind-only" and includes most Zen, Chan, and Seon Buddhist schools. It also includes a number of Tibetan Buddhist lineages. The conventional level is one composed of the appearances mind itself creates, and ultimate level is the mind-appearance inseparability.

The appearances are mind. The mind is also the mind, so reality is mind-only. The conventional reality exists as a "non-dual" or a "not-two" appearance of mind itself. The mind is real and self-established, but there is no "self-established person" who is unchanging. There is only the "non-dual all-there-is." This view places "awareness, mind, consciousness, or knowingness" at the center of training.

3. Madhyamika-Svatantrika. In this school, the Ultimate means a lack of “true existence” beyond mental designation. Things do posses properties, characteristics, distinctive features, and so on, but have no essence or identity which makes them what they are. Phenomena exist as mere valid mental construction, imputed upon self-existent or self-arising characteristics.

4. Madhyamika-Prasangika. The conventional is mere designation by mind onto a valid basis of designation. The ultimate is full emptiness (a full lack of characterization) of all phenomena. All phenomena lack relationships, identity, structure, characteristics, properties, and an essence.

When the mind draws boundary conditions such as "this and that have a relationship" on a valid basis of designation, then it exists and functions as such. But, from the side of undesignated or unconstructed ultimate reality, it is utterly devoid of self-borne identities, characteristics, relationships, and so on.

Nagarjuna, "I pay homage to dependent origination which is not ceasing, not arising, not impermanent, not permanent, not coming, not going, not identical, and not different, free from [mental] fabrication, and peaceful." The ultimate level is utterly free from existence, non-existence, both, or neither, which are all merely validly and invalidly socially constructed designations.

In Tantra, Dzogchen, and Mahamudra, they then point out that the awareness or knowingness aspect of experience is inseparable from the emptiness aspect in the ground condition: clear light, rigpa, or bliss-emptiness. But these terms are attempting to point-out a state without any boundary conditions, reference-points, parts, and so on.

There is no agent, no action, and no object acted upon. There is no subject, no object, and no inseparability or non-duality of the two. There is also no utter non-existence, nihilism, or nothingness.

This all perhaps brings up the question: "What is dependent origination? Doesn't it mean parts-whole or cause-effect? What is this dependent designation?" Dependent designation finds its bones in Sutra, it's organs in Nagarjuna, it's nerves and blood vessels in Dignaga, Dharmakirti, and Chandrakiriti, and it's skin and clothing in the writings of Tibetan yogis like Tsongkhapa and Ju Mipham. It means: "application of a term, name, symbol, sign, or denotation to a valid basis of designation."

This process of mental designation onto a valid basis is, from the Prasangika perspective, the only way in which phenomena exist. Emptiness in Prasangika does not mean “arises from causes” and does not mean “has parts.” Those two definitions of “dependent arising” do not pervade all phenomena. Only “merely designated” pervades all phenomena.

The parts and whole are merely designated. The cause and effect are merely designated. The subject and object are merely designated. Mind is merely designated. Space is merely designated. Time and impermanence are merely designed. Atemporality and permanence are merely designated. Emptiness is merely designated.

The confusion arises here because the first two types of analysis (parts-whole and cause-effect) are used as a skillful means to help move someone out of seeing things as inherent: “It has causes, so it is not self-established.” Or “It has parts, so it is not self established.” But in the end, you are still clinging to real parts or a real nexus of causes in Sautrantika.

If you are still clinging to real “parts out there” and a real “causal web that brings things into existence.” You are not perfectly free of mental fabrication. As Dogen says, “causes do not happen before effects, effects do not happen after causes.” When the effect is designated, the causal nexus occurs simultaneously as merely designated. The "causal nexus" is merely a valid and functional mental construct, which has no objective existence.

Similarly, when the whole is designated, the parts occur simultaneously as merely designated. When an object is designated, then the subject occurs simultaneously. If you are clinging to a real “mind-only” which exists in and of itself through a quality of giving rise to and knowing phenomena, then you are clinging to mind, in Chittamatra.

When anything is existing or not existing, it is only on the basis of mere designation onto a valid basis of designation. Therefore, phenomena do not objectively, intrinsically, or inherently exists, not exist, both exist and not exist, or neither exist and not-exist. There are no self-borne characteristics like in Bhavaviveka’s Svatantrika.

Things are not one, not many, not both, and not neither. That is the meaning of Prasangika emptiness: uncharacterized, referenceless, and without fabrication.

The "valid basis of designation" is a long discussion, but it has no self borne structure, characteristic marks, identity, causal web, etc. According to Dignaga and Dharmakirti it is the ineffable, undifferentiated ground that is designated. Because of this, form is emptiness. Emptiness is form. There is no distinction.

What appears already lacks inherent identity. If it occurs, then it's a mental designation. If it doesn't occur, then it's a mental designation. It was always empty. Therefore, the gate is gateless. There is no attainment and no non-attainment. There is no "person" to "gain realization," about how things already are. The ground condition is without reference points of existence and non-existence: that is your "buddha-nature" and "your face before you were born."

For example, there arises an ineffable, unconstructed ground condition, which can be divided into subject-object, and then the objective aspect can be further divided into a house, a kitchen, a body, and coffee cup. When the cup is there, the nexus of causes that brought the cup into being is also there. But both are only social agreement, confirmed through my ability to use the object within the social parameters associated with the term “cup.”

(sips coffee)

But when investigated, no aspect of the occurrence from top-to-bottom, left-to-right, front-to-back, inside-to-outside, and mind-to-matter can be found existing beyond a mere mental label. The rest of the Buddhist path - all methods - flow from this understanding.