The Twenty Kinds of Emptiness in the Mahāyāna Dharma

In Volume 51 of the Great Prajñāpāramitā Sūtra, the Buddha taught that the Mahāyāna has twenty kinds of emptiness, which bodhisattvas should cultivate and study. They are: inner emptiness, outer emptiness, inner-and-outer emptiness, emptiness of emptiness, great emptiness, emptiness of ultimate truth, emptiness of the conditioned, emptiness of the unconditioned, ultimate emptiness, boundless emptiness, emptiness of dispersion, emptiness of non-change, emptiness of intrinsic nature, emptiness of own characteristics, emptiness of common characteristics, emptiness of all dharmas, emptiness of unattainability, emptiness of non-nature, emptiness of self-nature, and emptiness of the self-nature of non-nature. The emptiness of worldly dharmas refers to non-existence, absence, non-being, and unattainability, whereas the emptiness of the tathāgatagarbha of self-nature refers to that kind of emptiness in which all marks of worldly dharmas are absent—different from worldly dharmas. Its essence exists and truly is, only it is not cognized in the way worldly dharmas are cognized. If one tries to cognize the emptiness of the tathāgatagarbha by the method of cognizing worldly dharmas, one cannot cognize it correctly and will often misinterpret it. The meanings of the twenty kinds of emptiness are explained briefly as follows:

Inner emptiness means that the inner dharmas—the eye, ear, nose, tongue, body, and mind—are empty. Outer emptiness means that the outer dharmas—forms, sounds, smells, tastes, tangibles, and dharmas—are empty. Inner-and-outer emptiness means that the inner and outer dharmas—the six inner sense bases and the six outer sense bases—are empty.

Emptiness of emptiness means that all dharmas are entirely empty, and this emptiness itself is also empty. Great emptiness means that the ten directions—east, west, south, north, the four intermediate directions, above, and below—are empty.

Emptiness of ultimate truth means that nirvāṇa is empty. Why is nirvāṇa empty? Because nirvāṇa is merely a tranquil state manifested by the essence of the tathāgatagarbha. A state, of course, is not a true dharma—let alone one that is merely revealed and displayed by the tathāgatagarbha. Do not confuse nirvāṇa with the essence of the tathāgatagarbha, failing to distinguish them; of the two, one is unreal and one is real.

Emptiness of the conditioned means that the three realms—the desire realm, the form realm, and the formless realm—are empty. The three realms are produced by conditioning and activity, and are therefore conditioned; dharmas that arise from non-existence into existence are naturally empty. Emptiness of the unconditioned means that these phenomena of arising, abiding, changing, and ceasing are empty; that is, the phenomena of arising, abiding, changing, and ceasing are empty, and the absence of arising, abiding, changing, and ceasing is something displayed, and is also empty. Existence and non-existence are merely provisionally established dharmas, mere verbal expression. Ultimate emptiness means that all dharmas are ultimately unattainable, and this unattainability is empty. Attainability and unattainability alike have no such thing; they are mere conceptual proliferation, and therefore empty.

Boundless emptiness means that among all dharmas, no dharma of the past limit, the present limit, or the future limit is attainable, and no limit of coming or going is attainable; the past, present, and future limits of the arising, development, and change of events are unattainable, and this unattainability is empty. That all dharmas have attainable past, present, and future limits is empty, and their unattainability is also empty; that all dharmas have limits of coming and going, development, and change is empty. For instance, sentient beings' past, present, and future lives are empty, and the absence of limits of coming and going is also empty; all phenomena, properties, and states whatsoever are empty.

Emptiness of dispersion means that the phenomena of all dharmas—disintegration, scattering, and abandonment—are empty; both gathering and dispersing are empty. Emptiness of non-change means that the phenomena of not altering, not changing, not dispersing, not scattering, and not abandoning are empty; both change and non-change are empty, both being mere conceptual proliferation. Emptiness of intrinsic nature means that the intrinsic nature of all dharmas is empty; whether it is the nature of conditioned dharmas or the nature of unconditioned dharmas, it is neither created by the Buddhas, bodhisattvas, śrāvakas, and pratyekabuddhas, nor created by ordinary beings. No one creates it, and therefore it is empty.

Emptiness of own characteristics means that the own-characteristics of all dharmas are empty. For example, the own characteristic of the aggregate of form is material impediment, and this is empty; the own characteristic of the aggregate of feeling is reception/feeling, and this is empty; the own characteristic of the aggregate of perception is grasping images, and this is empty; the own characteristic of the aggregate of formations is conditioning activity, and this is empty; the own characteristic of the aggregate of consciousness is discernment, and this is empty. In this way, the own characteristics of conditioned dharmas, or of unconditioned dharmas, are all empty.

Emptiness of common characteristics means that the common characteristics of all dharmas are empty. For example, the common characteristic of defiled dharmas is suffering, and this is empty; the common characteristic of conditioned dharmas is impermanence, and this is empty; the common characteristic of all dharmas is emptiness and non-self, and this is empty. Seen this way, the emptiness of the five aggregates and non-self realized by arhats is empty, and the twelve links of dependent origination realized by pratyekabuddhas is also empty. All dharmas have countless further common characteristics, and all of them are empty. Whether own characteristics or common characteristics, all dharmas are empty.

Emptiness of all dharmas means that the dharmas of the five aggregates, the twelve sense bases, and the eighteen elements—whether with form or without form, whether visible or invisible, whether with resistance or without resistance, whether defiled or undefiled, whether conditioned or unconditioned—are all empty.

Emptiness of unattainability means that all dharmas are unattainable, and even this unattainability is empty and unattainable. All dharmas, including the dharmas of the past, present, and future, are unattainable. If one takes a stand on the past, there is no present or future to be attained; if one takes a stand on the future, there is no present or past to be attained; if one takes a stand on the present, there is no past or future to be attained—and these unattainabilities are also empty. 

Emptiness of non-nature means that all dharmas have no properties or attributes whatsoever, and this very absence of nature is also empty. For example, water has no water-nature and no non-water-nature; it has no wetness or softness, no hardness or motility, and so on—no nature at all—and this absence of nature is also empty. For example, the five aggregates have no nature of the five aggregates and no nature of non-five-aggregates; they have no nature at all, and this absence of nature is also empty.

Emptiness of self-nature means that the self-nature of the dharmas' own essence is empty, their capacity for self-mastery is empty, and their capacity to combine and produce an own-essence is empty. Emptiness of the self-nature of non-nature means that the non-autonomy and non-mastery of dharmas is empty, and the mastery of dharmas by something else is also empty; that is, the capacity of dharmas to combine is empty, and the combined nature is also empty.

The existence, non-existence, self-nature, and other-nature of dharmas are all empty. Emptiness of existence means that the nature of the existence of the five aggregates is empty. Emptiness of non-existence means that the unconditioned nature of dharmas is empty. Emptiness of self-nature means that all dharmas have no self-nature of their own essence, and this emptiness is not accomplished by wisdom, not accomplished by view, nor accomplished by any other dharma. Emptiness of other-nature means that whether a Buddha appears in the world or not, the abiding of dharma, the fixity of dharma, the nature of dharma, the realm of dharma, the nature of equality, the nature of liberation from arising, suchness, non-falsity, unchangingness, and the limit of reality are all empty by reason of other-nature.

In short, whatever is verbally expressed has no real meaning; whatever is known and viewed has no real meaning; whatever is indicated has no real meaning; whatever notions there are have no real meaning; whatever deliberation and conditioning there are have no real meaning; whatever perceptions of dharma there are have no real meaning. Empty it all the way to the bottom, until reaching that which can no longer be emptied—that is the emptiness that is not empty. Apart from it, everything is empty.