Why Meditate? 
When you are caught up in the emotional upheaval of greed, anger and delusion, you may find yourself succumbing to some very real physical ailments; and when you are ill, the world may seem to be a very dismal place. That is not to say, however, that all of our illnesses are due to extreme emotions. Exposure to substances to which you may be allergic can alter everything about you. It can cause violent mood swings, depression, hallucinations and all sorts of physical effects, including actual tissue damage. Whatever the cause, disease is most often accompanied by an assortment of disruptive emotions. Programs that have been designed to make therapeutic use of relaxation methods and meditation have proved to be effective in curbing both the physical effects and the emotions which accompany them. Yet, as beneficial as they may be, such methods can take one only so far.

In the Buddhist tradition, meditation is used to defuse the source of all the trouble-the illusion of self and other. In Ch'an (or Zen), the aim is to overcome thought and defilement. Having done this, and with thoughts no longer stirring, the real substance of mind becomes evident. Without thoughts and without the illusion of self and other, greed, anger and hatred have no place to arise; and the energy that was tied up by those illusions becomes available, helping to provide an overall improvement in health. That is why meditation is called The Fundamental Practice.

The Psychophysiological Effects Of Meditation 
The Russian physiologist, Ivan Pavlov (1849-1936), emphasized the role that the cerebrum plays in physiology. At first glance, one might assume this to be merely a statement of fact, because that part of the brain is usually thought to involve little else other than thinking. Actually, it takes part in the production of many hormones, both directly and indirectly. Every aspect of a person is interrelated, and that is how and why thoughts and emotions can have such far-reaching effects. That is, however, also why meditation and calm-inducing thoughts can be so stabilizing and so healthy. One can safely assume, then, that most of what contributes to proper functioning also contributes to good health.

Useful Hints For Better Practice And Better Health 
As you progress in your practice, you are required to sit motionless for longer and longer periods of time at a stretch. It is then that some very important physical limitations may oblige you to make some adjustments in the way that you sit. Should you choose to ignore them, thinking that there is just one right way to practice, you may cause yourself needless pain and distraction (which means that you will not be able to concentrate); and you may possibly expose yourself to irreparable physical damage as well.

It is not unusual for people who have gone on retreats to return with painfully damaged knees, having held a position in spite of pain and having welcomed an ensuing numbness, simply because they have more trouble than they can remedy. To paraphrase The Kalama Sutra, "Do not do something because you have been instructed to do so, but try it and find out how it works for you."  Be always on guard for what doesn't seem to be quite right, and see what might be done about it. There are many, many methods that can be tried. There is no reason to have to submit to pain or outright debility, especially when nothing good can come of it.

The Relationship Between Mind And Meditation 
The metaphor of the mirror, often referred to in Ch'an, is most suitable here in pointing out the most salient aspects of meditation as practiced in this tradition. The mirror-mind does not respond at all, and it is by this lack of agitation that all things are clearly known. This is how the mind is said to be when there is no clinging. The mind, to be like a mirror, must be passive, detached, uninterested and quiet. It is a time of rest, recuperation and of learning to be undefiled in the midst of what is normally defiling. When there is no perturbation in the mind, just as when there are no ripples on the surface of a lake, all things are mirrored clearly, leaving no trace. There are no intentions, and there is no action to be taken or not taken. There is no dependence upon anything that you do or do not do. Meditation just unfolds naturally as the mind grows tranquil.

Concentration 
If you make the sun's rays converge, using a magnifying glass, and focus the resulting point of light onto a sheet of paper, you can easily burn a hole through it. Similarly, when you concentrate your thoughts, you are empowered in many ways. A lay Buddhist, Yang Jen San, once found a copy of The Surangama Sutra in an old bookstore. He was overjoyed. It was just what he had been looking for. He sat down and read and read in complete absorption, oblivious to his surroundings, until someone called him. Suddenly he noticed it had become dark and that if he wanted to continue, he would have to light a lamp. Wondrous things must happen in deep concentration, for he had been reading in the dark! A very famous writer of the Sung Dynasty, Su Dong Pu, recounted a similar experience in which he was so deeply engrossed in painting a picture that he was no longer aware of his person nor of anything else. It is as though where wholehearted application is directed, the whole world must step aside.

As your concentration strengthens, your breathing slows down and becomes subtle; areas of residual tension relax, perhaps after having existed there for a very long time, and there is no effort. A feeling of well-being and ease ensues. Sustained, relaxed concentration of this type easily becomes meditation. Unfolding naturally, if allowed to continue, it improves one's health and vitality, as stultified emotions and their physical concomitants give way to healing. The health-enhancing benefits of meditation are now a matter of record, and numerous physicians include it in programs for their patients' recoveries. 
The average person's mind is in turmoil. He or she is the product of deep-rooted patterns of thought resulting from karma accumulated since time immemorial, as well as being  tortured by the illusion of self. To be enlightened is to be free of all of that. Concentration already reduces the turmoil by limiting one's attention to just one thing. Through this practice, the apparent hold that you have on your illusion of self and things gives way until there is meditation. Then, there is an absence of thought and an absence of words. Then, without the stress and the strain of delusion, a very deep sort of healing takes place.

Meditation And Dhyana 
In Buddhism, the ordinary man is seen as leading a life steeped in suffering through the defilements of greed, anger and delusion. It is only when he finds out, firsthand, that there is, indeed, nothing that he does that is free of defilement and suffering and that there is a way out of it all, that he may become sufficiently well-motivated to gain that freedom. This is traditionally likened to the discovery that the pretty, colored rope that one has found and treasures is actually a very poisonous snake. When that is your experience, you may have such a profound understanding of Buddhadharma that your life will turn around radically. You may realize beyond all doubt that, though the body may be strong and healthy, it still changes and grows old. You may realize deeply, by breaking off attachment to both body and mind, that birth, death, and defilement also no longer exist. In the Ch'an tradition, this is discovered through meditation.

Discipline (sila), and wisdom (prajna)are closely related to meditation (dhyana). Proper discipline leads to dhyana,and dhyanagives rise to wisdom.It is by means of discipline that the defilements are dispelled, and this eases the way for the cultivation of dhyana(established in the same region as prajna). The great Ch'an Ting(Chinese for dhyana-related meditative practice) is said to be secluded from defilement and suffering as the result of self-discipline. To free oneself from defilements is the main purpose of the practice of pure discipline. By means of discipline, defilements are dispelled. Then, dhyanacan become established; defined variously as voidness, the absence of subject and object, Ch'an Ting,or that which is not of the flow of suffering, it is the access route to wisdom (prajna).