The undivided and real body of the Mind, the Tathagata is unborn.
This “unborn-ness”, is a non-tangible and indestructible essence with a highly dynamic and animative self-nature of sheer productiveness.
Was it not so you would not be able to walk and much less conceive thoughts or even enabling the “act” of talking.
Yet, we should be careful in that we do not try to think of it as one self or many selves. It is by virtue hence also known as the One Mind, [Huang Po], the Buddha Mind, The Unborn Mind and so on.
It is second to none in self-luminous supremacy and its unborn nature cannot be said to have a beginning and no end, as this would imply the limitation of temporality, relativity and thus uncertainty concerning its suchness.
Understand that this ultimate body of the Mind cannot be discerned by the senses, for the senses are in themselves an artificial composition by itself, for itself.
Anyone watching this will one day understand that what is seen, as a certain set of composed “dharmas”, only appears so because it is the perfect illuminative power of the dharma Mind itself that enables this “watching”.
In this realization, the once dissonant Mind slowly awakens to the fact that nothing self-existent is actually seen, but something is by habit translated as a composed separation from itself. Thus the belief arises that this “solid” separation must by certain causes be self-existent in itself.
When this Mind understands that it has been entrapped by its own mental “construction”, the sensually conjunctive self that is empty of the true self [the potential Buddha Mind] it focuses on finding its true self nature and when finding it, purifying it from old habits that once made it regenerate an artificial ghost in samsara, a ghost built on desires, fears and many other stored energies that constitutes a mental composition.
This act of self-realization, in the singular reality of the Buddha Mind, is an act of spiritual emancipation.
It is a corporeal-less act of facing the Minds solid and obscure wall [pi-kuan] of self-luminosity and thus the Mind trains itself to recall and accept this new reality as such.
The need of training is only there, because the Mind has an inbuilt flaw of becoming dissonant, anytime it reacts on vibrating energy signatures [phenomena], thus resisting the liberating power of that noble wisdom, which is so blissfully signifying for the Unborn Mind, The Tathagata.