We can use this explanation and categorization scheme to finally make sense of the various samadhi posed by several Indian yoga authorities, a task that has befuddled scholars and pundits over the ages.
If we take the writings of Patanjali's, Vyasa and Vacaspati Mishra (in his Tattva-Vaisharadi), we find a sequence of four samadhi whose degree of refinement increases in stages.
These samadhi, despite a difference in names, perfectly match with the four dhyana.
In fact this has to be so because the four dhyana are shared cultivation stages spanning all the different cultivation schools.
It is just that in Buddhism, their sequence and attainment is openly described in detail whereas in other schools they are not often so clearly commented upon.
In fact, in some other spiritual schools the commentaries on the dhyana are nonexistent because the founding (and subsequent) spiritual adepts just never got that far.
According to the classical Hindu yoga schools, a practitioner progresses through the samadhi by first gaining proficiency at a grosser stage of spiritual attainment, and by then developing dispassion toward this stage so as to progress to the next higher, subtler, purified, or refined level of meditative accomplishment.
Just as in the progression through the four dhyana, the higher realm of concentration is viewed as purer or more refined than the lower, but this purity is only relative.
Nevertheless, the mind is thus encouraged along a graduated process of refinement, all of which corresponds to higher and higher accomplishments within the Realm of Form.
The first samadhi in these schools is the vitarka samadhi, which is a samadhi still involved with the cogitation of thought that involves examining an object.
This is nothing less than the first dhyana, for none of the other dhyana are still involved with the vitarka of coarse mental grasping.
Thus the objects of vitarka samadhi meditation are rather coarse, namely the gunas of Hinduism and their products.
Vedanta, namely the Samkhya school of philosophy, offers a wide variety of suggestions for these objects of support, which are objects used as a point of focus in meditation.
For example, you can meditate on the five elements, on a material form (such as the sun, a flame, etc.), or on a deity such as Vishnu or Shiva, or even on the image of Jesus, or a chakra or Sanskrit letter.
All these forms serve as a point of focus in meditation so that a spiritual aspirant can generate one-pointed concentration and attain the state of samadhi.
Next we have vicara samadhi, which is a samadhi of just vicara.
The second and third dhyana of Buddhism can both be classified as just vicara, which is mental reflectionor observation, but the third dhyana is distinguished by the fact that it is characterized mainly by bliss (ananda).
Hence, the third dhyana corresponds to the stage of ananda samadhi, and the Hindu sage Vyasa confirms this understanding with the description: "Rapture is bliss."
This leaves the second dhyana as the sole correspondent for the vicara samadhi of classical Hindu yoga, and its stipulation as the second samadhi in the series matches up with the second dhyana ranking as well.
The last samadhi is asmita samadhi, which is described as a samadhi of merely I-am-ness.
This is the fourth dhyana where there is only one-pointed concentration and profound emptiness, but where the practitioner has not yet freed himself from the confines of the egocentric seventh consciousness.
He has reached a stage of selflessness, but it is not the complete selflessness of the Tao.
In summary, vitarka samadhi corresponds to the first dhyana.
Vicara samadhi corresponds to the second dhyana.
Ananda samadhi corresponds to the third dhyana.
Asmita samadhi corresponds to the fourth dhyana.
As the Hindu sage Vyasa says of the four Samadhi:
The vitarka-conjoint samadhi actually accompanies all four.
The second one, with gross thought (vitarka) having been terminated, is accompanied by subtle thought (vicara).
The third one, with subtle thought having been terminated, is accompanied by bliss (ananda).
The fourth one, with that bliss having been terminated, is merely I-am-ness (asmita).
All these samadhis are dependent on, conjoint with, or accompanied by supportive factors.
Even though you become free from random thoughts when you attain the fourth dhyana, it is not yet the highest stage of spiritual accomplishment one can reach.
All these samadhi involve supportive factors as the focus of concentration because they all correspond to attainments within the Realm of Form.
To progress even further in cultivation accomplishments, you have to also be able to attain the samadhi absorptions of the Formless Realm which are no longer involved with gross mental objects of support at all.
As a general principle, we can only say that the experiential realm of the fourth dhyana involves liberation from random thoughts to reach a deep state of clarity and calm.
We provisionally describe this stage as "empty," though there are emptier stages still.
All the dhyana have various graduations of achievement, and there are nine different levels of achievement within the fourth dhyana, each of which corresponds to a different Form Realm heaven due to the slight differences in psychology and merit.
Naturally you could subdivide any stage of concentration into as many levels as you would like, but Shakyamuni Buddha divided each of these dhyana into a specific number of stages based on a variety of factors, including the different merits they each imply.
While the Taoists, because of their emphasis on the physical nature, would describe the process of proceeding from the first to fourth dhyana in terms of jing, chi, shen and emptiness transformations,
Buddhist sutras describe the ascent according to the principles of mind (psychology) and merit.
Other schools may describe parts of this progression via biophysical kung-fu or other factors, but the Buddhist descriptions most closely address the heart of the matter.
Basically, Buddhist teachings say that the four dhyana are linked together in a graduated sequence of development in which each lower dhyana serves as the basis for the higher, and the higher in turn represents a more purified version of the lower states.
Thus, to attain the dhyana,
If they become separated from sensual desire and from non-virtuous qualities, a monk (cultivation practitioner) can enter into and abide in the first dhyana, in which there is conceptuality and analysis, joy and bliss, and which arises because of separation from hindrances. ...
Due to diminishment of the factors of conceptuality and analysis, he can enter into and abide in the second dhyana, which is characterized by internal tranquility, one-pointed concentration of thought,
which is devoid of conceptuality and analysis, but which has joy and bliss. ...
Due to detachment from joy, the monk will dwell in equanimity, have mindfulness and clear understanding, and experience the bliss in body and mind of the third dhyana. ...
Through eliminating both pain and pleasure, and due to the previous disappearance of sorrow and happiness,
the monk can enter into and abide within the fourth dhyana which is devoid of pain and pleasure, a state of equanimity and absolute purity of mindfulness.
All four dhyana's still belong within the domain of consciousness, so even though one attains the fourth dhyana, a spiritual practitioner has not yet escaped consciousness even though he has escaped from random thoughts.
These four dhyana constitute great spiritual cultivation attainments, but they do not constitute the whole spiritual path; there is still much more work to go.
It is very easy to attain various superpowers when you attain the various dhyana, but having attained various siddhis does not mean you have attained any of the dhyana!
Patanjali's Yoga Sutras devotes an entire chapter to supernormal powers which can developed from certain spiritual concentrations, so it speaks of all these things in detail.
For instance, it mentions that if you concentrate to master the chi currents that control the lungs and upper part of the body, you can walk on water.
If you can control the force that governs your chi, you can surround yourself with a blaze of light, which is akin to the Christian event of transfiguration.
You can also make your body as tiny as an atom, develop supernatural hearing, supernatural sight, knowledge of distant places and so on.
You just have to purify your chi and shen and then concentrate in the appropriate way to attain these special abilities, so of course this means accomplishing a one-pointed concentration within the realm of the four dhyana.
Simply by controlling the mind you can gain these supernormal abilities,
and while they can provide more insight into nature than is yet possible by modern science, they still are not the ultimate matter.
These, too, are just temporal abilities.
Buddhism mentions six types of psychic powers, but these are by-products which naturally arise due to progress made on the cultivation trail that ignores them.
There is the ability of supernatural sight, which allows you to see anywhere, the ability of supernatural hearing which allows you to hear sounds anywhere, the ability to know past lives,
the ability to know the minds of others, the extinction of outflows (the destruction of the afflictions of greed, hate, stupidity or desire),
and the "complete spiritual penetration" which entails miraculous supernatural abilities such as being able to fly through space,
become invisible, transform one object into many or many into one, or appear anywhere at will.
Buddhism also mentions "five eyes," or five types of vision that you will naturally attain from cultivating the correct spiritual way.
There is a saying that summarizes these "Five eyes" and their penetrations:
Supernormal powers themselves are just functions of the realm of consciousness because they are actually the result of various machinations of thought.
Thus, they cannot be considered anything special other than a particular way of holding the mind.
In this sense, even having a good memory can be considered a type of superpower, but people do not realize this.
Furthermore, just because someone has attained various siddhi superpowers and psychic abilities does not mean they are a more spiritual or "advanced" person than other individuals.
We often see this strange view promoted on television or in the movies, whereas psychic abilities can originate from sickness or mental instability.
If someone is hit in an accident such that it opens their chi mai, it is possible to attain all sorts of strange psychic abilities.
Even demons and ghosts have psychic abilities and superpowers, so possessing them does not mean you are spiritually exceptional.
However, such are the misconceptions people tend to base themselves on when trying to judge someone's level of spiritual cultivation achievement.
Frankly, most cultivation practitioners who develop and then widely demonstrate these abilities--such as supernatural hearing and sight, being able to know the future or being able to project their chi--tend to get dragged down by such powers.
These various abilities are just obstructions on the path because they can cause people to lose sight of their original aims and goals in cultivation.
The reason someone can cultivate the four dhyana is because they have accumulated enough merit and put in the required cultivation efforts. Cultivation practice, plus patience, plus time, produces this result.
Although the four dhyana are important vehicles on the path of realization, we cannot consider they are what is fundamental in Buddhism.
They might be hard for ordinary people to attain when they do not put in the requisite meditation efforts, but they still represent an incomplete level of attainment in the overall scheme of cultivation experience.
The real accomplishment of Buddhism or any religion is to see the Tao and attain enlightenment.
Nonetheless, we cannot fault the four dhyana in any way, and must recognize that they are common stages of the spiritual cultivation path shared by all schools of genuine spirituality,
so you must become familiar with these stages and learn their various characteristics as well as the general level of attainment which they represent.
They do not yet embody the ultimate, but they are still a common measuring stick of the spiritual progress you can make toward this goal.
As we have mentioned, each of the four dhyana can be broken into finer graduations, each of which corresponds to slightly different conditions of accomplishment.
This is a common characteristic of any measuring system, for even the five skandhas can be further sub-divided into various categories.
Thus, on a similar note, it is not surprising to find that the state of no-mind (mindlessness, nonperception, or "not having mind" or "no-thought") traditionally has five different situations, called "stations," where it can occur:
There is also the "nirvana without remaining dependency" achieved by the Mahayana Bodhisattvas and Buddhas.
This is the only correct form of "having no mind," for in this stage the ignorance of the alaya consciousness becomes extinct as it transforms into the great mirror wisdom.
That is when you reach the purity of inherent true nature.
We sometimes say that a Buddha is omniscient because the great mirror wisdom is eternally present to all objects without failure of memory or perceptive error.
When you return to your fundamentally enlightened status, this wisdom is your naturally existent state.
In cultivation, there are also several states that involve an empty gap between two moving processes, and this intercessionary gap of peaceful stillness, called a bardo state, is often used as a point of focus for spiritual cultivation.
For instance, this type of gap can occur:
All these intercessionary situations can and do serve as the basis for particular methods of cultivation.
For instance, recognizing that gap of no-mind between thoughts is cultivation of the cessation and contemplation practice of the Tien-tai school.
When you practice to recognize the state between waking and sleeping (as is common in many yogic schools), or between
dreaming and not dreaming, this is related to the dream yoga of the Esoteric school.
Cultivating the gap between the in-breath and out-breath is the basis of anapana or pranayama practice, and all the other breathing practices of the world.
And the state immediately after death that proceeds rebirth--the bardo state--is the focus of the various Tibetan bardo cultivation practices for attaining enlightenment.
The adherents of Kashmir Shaivism even make a science out of contemplating the state of contact or no-contact with a physical or mental phenomenon, so there are many states with a "gap" that can be used as an entry point of focus for entering into samadhi.
In most all the cultivation techniques based on intercessionary phenomena, people try to focus on that gap of emptiness between two states of movement.
You do not focus on the states of movement themselves, which are akin to the birth and death of the volition skandha, but on that peaceful state of empty stillness between them.
If you concentrated on the moving things you would be concentrating on birth and death, or the transient things rather than the thing which stays.
During that peaceful intercessory situation, the sixth consciousness is inactive for a moment, and discursive thought is therefore relatively nonexistent.
This gap of pausation is not the Tao itself or the prajna emptiness of cultivation doctrine.
It is just a momentary calming of the sixth consciousness.
However, various cultivation techniques can be built around this empty situation into order to familiarize practitioners with some understanding of emptiness, as well as help them enter into the first dhyana.
You need some type of method for entry into the dhyana; these are just some of the methods available.
These particular cultivation techniques are just the minor initiatory methods that can help practitioners familiarize themselves with emptiness, after which they can deepen their understanding so as to eventually "see the path."
While none of these situations correspond to the true wisdom emptiness of cultivation, techniques that focus on these resting situations can help practitioners familiarize themselves with the meaning of the path.
With continued practice of such techniques, in time spiritual cultivators will gain some cultivation accomplishment and eventually recognize the true way to spiritual enlightenment.
Therefore, none of these states are the actual samadhi of emptiness espoused by Hinayana cultivation, nor are they the prajna of emptiness either.
But you can build definite methods of cultivation practice around these states, and pursuing these methods can indeed help you enter into samadhi.