The difference between the Perfection and Mantra Vehicles must apply to one of the two meanings of “vehicle”: the means by which one proceeds or the fruit to which one proceeds. There is no difference in the fruit, Buddhahood; hence, the difference rests in the sense of “vehicle” as the means by which one progresses to that fruit.
The Great Vehicle surpasses the Lesser Vehicle in terms of method, the altruistic aspiration to highest enlightenment for the sake of all sentient beings, and the division of the Great Vehicle into a Perfection Vehicle and a Mantra Vehicle is also made by way of method. In general, the paths included within the factor of method are the means for achieving a Buddha’s Form Body, whereas the paths included within the factor of wisdom are the means for achieving a Buddha’s Truth Body. To achieve a Truth Body one needs to cultivate a path similar in aspect to a Truth Body, and both the Perfection and the Mantra Vehicles have a path of wisdom in which one cultivates a similitude of a Buddha’s Truth Body: the realization of emptiness in space-like meditative equipoise.
In order to achieve a Form Body, one needs to cultivate a path that is similar in aspect to a Buddha’s Form Body. Only Mantra has the special method for achieving this feat by cultivating paths that are similar in aspect to a Buddha’s Form Body. The presence of meditation that utilizes a similitude of a Form Body is the greatness of the Mantra method; such is not set forth in Sūtra.
In order to remove mental defilements it is necessary to meditate on emptiness, but this is not a complete method for achieving Buddhahood because meditation on emptiness only removes the conception of inherent existence and all the afflictions that are based on it; other practices are needed in order to achieve the physical perfection of a Buddha. The complete method capable of bestowing Buddhahood quickly is the cultivation of a path of deity yoga in which the pride of being the deity of the effect state is established.
The attainment sought is the state of a Buddha endowed with the marks and beauties. To achieve this state one must train in the path of a divine body similar in aspect to the body of a Buddha. Therefore, cultivation of a divine body is not used merely for the achievement of common feats but is essential for achieving the uncommon feat of a Buddha’s Form Body.
According to the Perfection Vehicle, in order for the wisdom realizing emptiness to serve as an antidote to the obstructions to omniscience, it must be conjoined with altruistic mind-generation and practice of the perfections. The vast methods such as giving, ethics, and patience help limitless sentient beings, and their imprint at Buddhahood is the achievement of Form Bodies which perform limitless altruistic activities.
The wisdom penetrating the depth of the suchness of phenomena is the means for actualizing the nonconceptual wisdom of a Buddha. Thus, the special imprint of the collection of wisdom is the attainment of the Wisdom Truth Body coupled with the abandonment of all contaminations.
Neither a Truth Body nor a Form Body is attained singly because they both depend on completion of these causal collections of method and wisdom. The two collections act as cooperating cause and special cause of the Truth and Form Bodies. For example, an eye consciousness is generated in dependence on three causes, an object, an eye sense, and a former moment of consciousness; the ability of an eye consciousness to apprehend color and shape rather than sound is the imprint of the eye sense; its being a conscious entity is the imprint of an immediately preceding moment of consciousness; and its being generated in the image of a particular object is the imprint of the object. Just as each of the three causes is said to have its own individual imprint in the generation of the eye consciousness, the imprint of wisdom is a Truth Body and the imprint of method is a Form Body.
Because the Perfection Vehicle sets forth a method for achieving the nonconceptual Wisdom Body of a Buddha and the Form Bodies effecting limitless maturations of other beings’ minds, it is said to have unsurpassed method. However, in the path of the Perfection Vehicle, the causes of highest enlightenment are explained as only the six perfections. These are not sufficient because through cultivating causes such as giving, ethics, patience, and so forth—that are different in aspect from Form Bodies, the fruit—one cannot actualize the enlightenment of a Buddha. One would be attempting to actualize an effect that is different in aspect from the causes. The effect of Buddhahood, which has a nature of profundity—a Truth Body—and vastness—a Form Body adorned with the marks and beauties—in one undifferentiable entity, is achieved from causes that have a similar nature. Just as one meditates on the meaning of selflessness that is similar in aspect to a Truth Body, so one should cultivate paths of vastness that are similar in aspect to a Form Body.
In the Mantra Vehicle the “vast” refers to the appearance of a divine body. There is a vastness at the time of the path—cultivation of the vivid appearance of a divine body coupled with divine pride—and a vastness at the time of the fruit—an ultimate vastness that achieves the welfare of others. Deity yoga is “vast” because deities such as Vairochana, who are qualified by emptiness and included within the factor of appearance, are inexhaustible, continual, limitless, and pure. Even though both pure and impure phenomena are qualified by emptiness, there is said to be a difference due to the phenomena qualified by it.
In Mantra, conjunction of method with wisdom and vice versa means not that method and wisdom are individual entities which are merely compatible with each other but that they are complete within the entity of one mind. Based on cultivating this union of method and wisdom, at Buddhahood the Truth Body of nondual wisdom itself appears as the features of a deity. Therefore, prior to meditating on a divine body it is necessary to establish through reasoning the absence of inherent existence of oneself; then, within the context of meditating on this emptiness, just that mind which has one’s own emptiness as its object serves as the basis of appearance of the deity.
Induced by ascertaining the emptiness of one’s own inherent existence, this consciousness itself appears in the form of the face, arms, and so forth of a deity. Wisdom vividly appears as a divine body and at the same time ascertains its absence of inherent existence. These two—wisdom realizing the absence of inherent existence and the mind of deity yoga—are one entity, but posited to be different from the viewpoint of their imprints. Thus, from a conventional point of view method and wisdom are different within the context of being one entity. They are said to be different in that method is the exclusion of nonmethod and wisdom is the exclusion of nonwisdom.
Based on the appearance of a divine body, the pride of being that deity develops, having ultimate and conventional aspects. Some scholars say that the appearance of a mind ascertaining emptiness in the form of a deity means that this one mind has emptiness as its referent object and a divine body as its appearing object. Thus, the consciousness has a factor of ascertainment—the understanding of a negative of inherent existence—and a factor of appearance—the vivid reflection of a divine body. In this way, divine pride has two aspects, observing the ultimate—emptiness—and observing the conventional—a divine body.
Among the sūtra explanations there are two systems with regard to whether a phenomenon qualified by emptiness appears to a mind that inferentially realizes that emptiness. Some say that an object qualified by an empty nature appears during inferential realization of its emptiness, and others say that the appearance of the object is no longer present when its emptiness is being understood. In Tsongkhapa’s Great Exposition of the Stages of the Path Common to the Vehicles, it seems that the phenomenon qualified by emptiness does appear to an inferential consciousness realizing emptiness, but in some monastery textbooks the opposite is held. In any case, initially one meditates on an emptiness, and then, within the context of the mind’s continuous ascertainment of emptiness, meditators believe that they are using this mind as the basis [or source] of appearance. At that time, the sense of a mere “I” designated in dependence on the pure resident—the deity—and residence—the palace and surroundings—is a fully qualified divine pride. As much as one can cultivate such pride, so much does one harm the conception of inherent existence that is the root of cyclic existence.
This composite of method and wisdom—the appearance of a deity empty of true existence, like an illusion—is an affirming negative, an absence of inherent existence as well as a positive appearance. One gradually becomes accustomed to this mind, and finally when one arrives at high levels on the stage of completion as explained in Highest Yoga Tantra, the union of a learner is attained in which a continual similitude of a Form Body and a Truth Body is actualized. These are a “Form Body” on the occasion of the path and a wisdom of clear light, which are the actual substantial causes of Buddhahood.
Thus, Mantra is distinguished from the Perfection Vehicle through its superior method for the achievement of a Form Body. Mere meditation on a divine body that is not related with meditation on emptiness is not sufficient. On the other hand, mere meditation on emptiness is also not sufficient. Even though it is not possible to attain Buddhahood in dependence on the paths of the Perfection Vehicle alone, the Perfection Vehicle does set forth paths for the achievement of Buddhahood. If one engages in these paths, meditating on emptiness and cultivating the features of method as explained in the Perfection Vehicle, then it is said that one will attain Buddhahood only after many countless eons; one cannot attain Buddhahood quickly. Actually, one cannot attain Buddhahood through causes that do not have an aspect similar to the effect, a Form Body. In brief, the Body of a Buddha is attained through meditating on it. One should meditate on a divine body until its features appear clearly and steadily, until it seems that one can touch it with one’s hand and can see it with one’s eye.
Someone might think that in the Perfection Vehicle one cultivates a Buddha’s Form Body through meditation involving prayer petitions to attain such. However, if that were the case, one would not need to meditate on emptiness in order to attain a Truth Body; planting prayer petitions would be sufficient. However, Buddhahood is attained through the nondual yoga of the profound and the manifest; without it Buddhahood is impossible.
This is established not only in Highest Yoga Tantra but also in the other three tantras. In Action and Performance Tantra a Truth Body, which is said to be thoroughly pure in the sense of being free of all dualistic proliferations, is achieved through the yoga of signlessness—meditation on emptiness—and a Form Body, which is said to be “impure” in the sense that it is involved in duality, is achieved through the yoga with signs—deity yoga. In Yoga Tantra deity yoga is presented in conjunction with five factors, called the five manifest enlightenments.
This yoga of the union of the profound and manifest is the path of all the chief trainees of the Vajra Vehicle but not necessarily of all trainees of the Vajra Vehicle. For those who cannot imagine themselves as deities, the practice of contemplation of a deity in front of oneself is set forth in conjunction with repeating mantra, making petitions, and so forth. The chief trainees in terms of whom the Vajra Vehicle was taught are those capable of practicing the full Mantra path, and generating oneself as a deity is definitely taught for all chief trainees. The modes of meditation for the achievement of feats, such as the techniques for meditating on the winds (prāṇa), are all for the sake of either making deity yoga more firm or enhancing realization of suchness.