In Tantra, body refers not only to the gross but also to the subtle or the psychic, as well as to the cosmic aspects of the physical body. Hence the body is to be understood as a psycho-somatic as well as a cosmic entity. It is a fundamental tantric insight that the body is the abode of all truth. Body helps a yogi to attain the ultimate realisation.
The great knowledge that the body holds is that the nature of the Absolute is bliss and that it pervades all beings. This bliss can be experienced only in the body and only in reference to the body can the Absolute be spoken of as bliss. At the same time it does not mean that bliss is ultimately dependent on the body because it has been clearly stated that though it is in the body it is not of the body.
Bliss in itself is independent of the body, but bliss as an object of experience cannot be had except in the body. This again accentuates the centrality of the body in the tantra. It has been said that the bodily experience of pleasure is but a glimpse of the same absolute bliss, which is the nature of all beings. Bliss is said as absolute and relative; as absolute it is the enlightened consciousness.
It has been said that the tantric sadhana is performed in and through the body. Hence an understanding of the Yogin`s body is essential. As a result three most important parts of the Yogin`s body has been considered in order to understand the centrality of the body. The important body parts of the Yogin which have been considered are namely the spinal cord, the plexus and the nadis. These parts constitute the anatomy of the yogin`s body.
The spinal cord is central to tantric physiology. It is called the spinal cord and is identified with Mount Sumeru. It has been also described as the caves of the highest truth where the entire world vanishes away. It is along the spinal cord that the chakras are visualized and it is through it that the nadis pass. Hence the steady vertical position of the spinal cord is insisted upon in all yogic meditative practices.
There are four plexus (chakras or lotuses). In Tantric Buddhism the four chakras are associated with the four kayas. The Body of Creation is proclaimed to be there from where all living beings are born, the act of creation being constant and age-old. Since it generates that is creates it is known as Creation. Nature refers to the nature of consciousness and the Body of Essential Nature is located in the heart. "Enjoyment" is the enjoyment of the six flavours and the Body of Enjoyment is located in the throat. The Centre of Great Bliss is located in the head.
The four kayas are associated with the four Beings. Since these manifestations of the Absolute are the kayas and the kayas are located in the chakras it may be said that body is the abode of truth. The nadis form another component of the tantric physiology. It has been said that thirty-two important nadis bear bodhichitta and flow into the Centre of Great Bliss. Of these nadis three are most important they are namely lalana, rasana and avadhuti.
Lalana is believed to start from the neck and enters the naval region from the left side. Rasana starts from the navel and enters the neck from the right. Within these two and passing through the lotus in the heart is the avadhuti. Avadhuti is so called because it is that which destroys all sins through its effulgent nature.
In the Tantras the body is viewed as a microcosm. It is a microcosm because it embodies the truth of the universe. Moreover the constituents of the universe are identified with parts of the yogin`s body. It has been said that the body finds expression through the tantric dance. Within the body the whole existence is experienced and expressed. The whole realm of existence is within the body in the form of nadis.
In Tantric Buddhism the body, speech and mind are associated with the three kayas namely the nirmanakaya, sambhogakaya and dharmakaya respectively. The unity of these three centres is spoken of as the fourth centre namely the mahasukhachakra at the top of the head. Body, speech and mind are called trayo vajrinah and their unity is called tribhavasyaikata which is the state of non-duality The Body, Speech and the Mind are also called the three secret three and are spoken of as located in the centre of the mandala in the form of three goddess. The sadhaka is to correlate his body, speech and mind to those of the Buddhas. He correlates the body by means of gesture, speech by means of incantation and his mind by means of intense concentration. Tantric Buddhism perceives that existence is nothing but Body, Speech and Mind and by making them adamantine existence itself is transmuted. This is the ultimate goal of tantric sadhana.
A `homologous-vision` of reality is another fundamental aspect of tantric thought and praxis. Homology means correspondence or similarity in structure but not necessarily in function among the corresponding entities. Tantric vision is of constant correspondence between the external and the internal. There is perfect conformity between the outer rite and the inner one and vice versa. In fact it can be said that this doctrine of Tantric Buddhism demonstrates the identity of the macrocosm with the microcosm, or the psycho-somatic with the cosmic. On the other hand it can be said that since everything is essentially essence-less everything corresponds to everything else.
Hence it can be concluded saying that according to Tantric Buddhism the body is the microcosm, the abode of all truth. It is within the body that the entire universe is located, discovered and experienced. The insight that the Absolute is mahasukha is fundamental to Tantric Buddhist thought and praxis and it can only be experienced within the body. Once the Absolute is realised all aspects of existence appears as one homologous vision. The enlightened one discovers that everything corresponds to everything else in an inexplicable manner.