From the point of view of absolute truth, phenomena have no actual entity. What we think of as ‘I,’ ‘my body,’ ‘my mind,’ ‘my name,’ have no real existence either. Other beings have no real existence either, whether they be dangerous enemies or loving parents. In the same way, the five poisons are by nature empty. Bearing this fact in mind, we should watch from where these poisons, these negative emotions, arise: what does the agent of these arisings look like, and what do the emotions themselves look like? If we analyze, we shall find nothing. This absence is the unborn dharmakaya (Truth Body).
Although everything is by nature empty, this emptiness is not the mere vacuity of empty space or an empty vessel. Happiness, sufferings, all sorts of feelings and perceptions appear endlessly like reflected images in the mind. This reflection-like appearance of phenomena is called the nirmanakaya (Manifestation Body).
A grain not planted in the soil will never give a fruit; likewise that which is unborn will never cease to be. To be beyond origination is to be beyond cessation also. This aspect of unceasingness is what should be understood as the sambhogakaya (Enjoyment Body).
If there is neither birth in the past, nor cessation in the future, there cannot be something which endures in the present; for an existence necessarily implies a beginning and an end. The fact that the mind is by nature empty, that it is nevertheless the place where phenomena appear, and that it is beyond origination and is therefore unceasing, this inseparable union of the three kayas is called the svabhavikakaya (Natural Body).
If deluded perceptions are understood in terms of the four kayas, it follows that in that which is termed deluded, there is nothing impure, nothing of which to rid ourselves. Neither is there something else, pure and undeluded, which we should try to adopt. For, indeed, when illusion dissolves, undeluded wisdom is simply present, where it always has been.
When gold is in the ground, for example, it is blemished and stained, but the nature of gold as such is not susceptible to change. When it is purified by chemicals or refined by a goldsmith, its real character increasingly shines forth. In the same way, if we subject the deluded mind to analysis, and reach the conclusion that it is free from birth, cessation, and abiding existence, we will discover, then and there, a wisdom which is undeluded.
Furthermore, the deluded mind, being itself illusory, is unstable and fluctuates, like experiences in a dream, whereas the true and undeluded nature of phenomena, the Buddha-nature or Tathagatagarbha, has been present from unoriginated time. It is exactly the same in ourselves as it is in the Buddhas. It is thanks to it that the Buddhas are able to bring help to beings; it is thanks to it, too, that all beings may attain enlightenment.Excerpted, with minimal editing, from Enlightened Courage, by HH Dilgo Khyentse Rinpoche.