Kumarajiva’s work, The Essential Explanation of The Method of Dhyâna (C., Chanfa Yaojie) likens the fourth and highest dhyâna (or Zen) to the top of a mountain; which is also unmoved (the unmoved samâdhi). The previous three dhyânas are more like stepping stones or a path up the mountain. They are not the top or the true dhyâna. Thus true dhyâna is Mind that is pure and clear.
One can imagine doing these dhyânas in seated meditation in a place far from the madding crowd; that would be perfectly okay. But there is much more to this than meets the eye at first glance. Using myself as an example, I was totally clueless as to what the Indian Buddhist notion of mind or citta was. One would be closer to understanding the Indian notion of mind to think of it as something completely spiritual which also includes within it both the physical and the psychological. We might also call it the animative principle or the life force or even the Christian, light of life.
If Western Zennists do not treat Mind or spirit as absolutely real—not just as a metaphor—they will become lost and disillusioned. There is no way to understand the Mind to Mind transmission except this way. Understandably, the average person doesn’t sense anything like this because they are overly attached to the animated corpse they cling to which causes their minds to become grossly defiled. It’s like a dirty mirror—so dirty—that it can’t even reflect the sun.
As impossible as it seems, the point of dhyâna is to get in touch with the Mind that is pure and clear. This is the apex of dhyâna. All else follows from this. The Four Immeasurable Minds (catvâri-apramânâna) can be easily attained with the fourth dhyâna. Also, the Four Noble Truths, the six supernatural powers, etc.