Anyone who makes a cursory survey of the classical documents surrounding Nei Dan meditation in the Daoist Canon will quickly come to discover that the actual mechanics of meditation are not very complicated, but there is an absolute wealth of knowledge about how to correctly cultivate and gain the beneficial effects of meditation.
Why is this?
Although the mechanics of Nei Dan are not complicated, learning to affect the correct type of attention and how to control it is key to the early stages of practice.
Beyond this, learning how to interpret the physical manifestations of practice and what they mean is very important.
For instance, Someone who is new to meditation might begin to feel the sensation of their body disappearing into infinite space, and if they did not have any frame of reference for this, might become nervous and afraid and thus not gain the full benefit of the free movement of energy and consciousness in the body.
As another example, many modern writers of Qi Gong in the west have misinterpreted Daoist ideas such as the movement of energy along the orbit running up the spine and down the front of the torso as being something which should be moved with the intention. Classical Nei Dan theory views this type of intentional orbit as superficial and incorrect to the development of a strong and robust energy body with a full reservoir of energy accumulated in the lower Dan Tian.
If it were simply the case, that meditation classics discussed the movement of energy and not the reasons why energy accumulates or how non intention interacts with the spontaneous movement of energy, then it would be even more common for charlatans to gain the popular imagination by offering simple and quick approaches, to what is otherwise a long and involved study.
Nei Dan theory is also complicated because it has developed over multiple generations and at least six major dynasties and into the modern era. This means that the gradual accumulation of collected knowledge on the subject has allowed Nei Dan to proliferate as something much more profound and complex than its humble roots as “Embryonic breathing.”
This extra complexity isn’t added purely for intellectual effect, it was added because over time, people who practiced Nei Dan began to have the diagnostic tools by which they could more accurately record their experiences and pass them along to future generations, in order that their practices might be better organized than those of past generations of Nei Dan practitioners.
The Nei Dan school has one of the richest collection of documents on the theory and philosophy of meditation available in any tradition and the practices of Nei Dan have been very well preserved by each subsequent generation in the passing down of traditional texts and the creation of new ones, each serving to meet the needs of the next generation of practitioners, who would gain the immense benefit that meditation has to offer to body, spirit, and mind.