The Three Bodies concept of Buddhahood is best understood in conjunction with the Two Truths concept. Yes, there was a man named Siddhartha Gautama who taught his philosophy in ancient India roughly 2,500 years ago. And yes, that philosophy is the embodiment of a transcendent truth which cannot be capably encapsulated by one person and their experience. But while one a basic, obvious truth, the other is a higher, transcendent truth.
The Nirvana Sutra involves a discourse in which the Buddha explains that his “dharma-body” will survive as long as his followers continue to follow his teachings. The Dharmakaya is the transcendent, immaterial, and all-pervading presence of the Buddhadharma. The teachings of the Buddha compose the Dharmakaya. Yet, the Buddha himself and all perfectly enlightened beings like him are emanations of the Dharmakaya. There are three dimensions of the Dharmakaya in the wisdom literature.1 First is the corpus of the Buddha’s teachings. Second is the dharmas possessed by the Buddha which grasp the concept of pure emptiness. Third is emptiness itself. These dimensions all share the trait of incorporeality.
The Vajrayana tradition takes the Trikaya concept a few steps further. In the parlance of Vajrayana literature, the historical Shakyamuni Buddha is one of a thousand Buddhas of the “auspicious aeon.” These are the Buddha-bodies of Form, accessible to sentient beings. The Buddha-body of Emanation is the visible body of the Buddha which arise.
The Sambhogakaya is distinguished from the Dharmakaya in that it is an impermanent, physical presence. Traditional Mahayana accounts claim that the teacher who expounded the Dharma in ancient India was not just a man born Siddhartha Gautama, but an emanation of the Dharmakaya bearing all the physical marks of a perfect being: a Samboghakaya, or a “Body of Complete Enjoyment.”2 The illusion of a man preaching in ancient India dissipates to reveal a Body of Complete Enjoyment teaching in a Buddha Field.3
The Nirmanakaya, or Transformation Body, is the physical manifestation of a Buddha. The historical Buddha is the consummate example. The body of Siddhartha Gautama is the manifestation of the Buddha in the age of ancient India. The words of this Buddha are the words which constitute the Pali Canon.
The Trikaya concept precludes the existence of icchantika, who are beings destined to never attain Buddhahood.4
Sanskrit: Trikāya, Dharmakāya, Saṃbhogakāya, Nirmāṇakāya
1Williams, 1989, 173.
4Takakusu, 1947, 128.