有人问我：“入定和睡觉有什么不同？”简而言之，入定的姿势，仍然端坐，背直如笔，端正不偏，或者呼吸停止，或者脉搏停止，望之，好像活死人，但有知觉。可以坐一天不动，十天不动，甚至一个月不动。睡觉的姿势，头歪身斜而不自主，气出气入，呼呼有声，甚至鼻息如雷。不同之处，就在这个地方。
Someone has asked, "What is the difference between samadhi and sleep?" To put it simply, people who are in samadhi will be sitting in an upright posture with perfectly straight backs, not leaning in any direction. Perhaps their breathing will stop or their pulse will cease, so that they appear to be dead; however, awareness and perception remain. Someone in samadhi can sit for an entire day, for ten days, or even for a month without moving. If a person is asleep, however, his head is usually askew, his body is leaning, and he is not in control of himself. He still breathes, and his breathing may be as noisy as thunder. These are the differences.
参禅的过程，好像读书一样，由小学、中学、大学，然后进研究所，经过这四个阶段，才能获得博士学位。参禅这个法门，亦复如是，分为四个步骤，也就是四禅的境界。简略述之如下：
The process of Chan meditation is just like that of studying. One proceeds from elementary school to high school, then to college, and then on to graduate school, passing through four stages before one can earn a Ph.D. Likewise, the Dharma-door of Chan meditation is also divided into steps, the Four Stages of Dhyana-concentration, which are briefly explained below:
初禅名“离生喜乐地”。就是离开众生的关系，得到另外一种快乐。此非凡夫所得的快乐，而是在自性功夫里边。到初禅定中，呼吸停止。外边呼吸停止，内边呼吸活动起来，好像冬眠一样的道理。这时，心清如水，明如镜，照了自性的本体，而知道自己在打坐。
The First Dhyana is called the Stage of the Happiness Leaving Birth. It takes you beyond what living beings can experience, into a state of happiness beyond what ordinary living beings know. This happiness is found in the spiritual skill of our inherent nature. When you reach the samadhi of the First Dhyana, your breath ceases. Your outer breathing stops and your inner breathing begins to function, just as if you'd entered a state of winter hibernation. Your mind at this time is as pure as water and as clear as a mirror. You can know your fundamental identity and can be aware that you are sitting and meditating.
二禅名“定生喜乐地”。在定中，出生一种无比的快乐，所谓“禅悦为食，法喜充满。”得到这种快乐，不知道饥饿，所以可以多日不食不饮，没有关系。但是不可以 执著，如果一执著，前功尽弃，就入了魔境，吾人不可不谨慎。二禅的境界，在定中不但呼吸停止，而且脉搏也停止。出定时，又恢复正常。
The Second Dhyana is called the Stage of the Happiness of Producing Samadhi. In a state of concentration, an incomparable happiness comes forth. We refer to it as "taking the bliss of Dhyana as food and being filled with the joy of Dharma." Happiness such as this leaves one unaware of hunger. Thus you can sit for many days without any problem. However, you must not become attached to this state, for as soon as you become attached, all your previous efforts will be wasted and you will enter a demonic state. So you must be extremely careful. At the stage of Second Dhyana, not only does the breath stop, but the pulse stops as well. When one leaves concentration, these processes resume their normal functioning.
三禅名为“离喜妙乐地”。就是离开二禅之欢喜，得到妙不可言的快乐，觉得一切都是佛法，一切都是快乐。三禅的境界，在定中呼吸脉搏停止，意念也停止。这时候，不念善、不念恶，不念是、不念非，也就是一念不生。但不要认为了不起，这仅是一个过程而已，离了生脱死还有十万八千里。
The Third Dhyana is known as the Stage of the Wonderful Bliss of Leaving Happiness. One reaches a wonderful, inexpressible happiness that leaves behind the happiness found in the Second Dhyana. You feel that absolutely everything is part of the Buddhadharma, and everything is a source of joy. In this stage, not only do the breath and the pulse stop, but the thinking processes also cease. At this point, you no longer think of good or evil, or right or wrong; not even a single thought arises. All the same, you mustn't feel that such a state is extraordinary. It's simply one step along the way, and it's a million miles away from putting an end to birth and death.
四禅名为“舍念清净地”。在此境界，连快乐的念也没有了，已把它舍弃，而到达清净无所作为的境界，也就是到了无为而无不为的地步。到了四禅，乃是参禅功夫所必经之路，没有什么不得了，不要误认是证果。如果这样想，就和无闻比丘犯同样的错误，而堕地狱。
The Fourth Dhyana is known as the Stage of the Purity of Renouncing Thought. At this stage, not even the thought of happiness remains. You've already done away with it, and you've come to a state of purity in which there's no further action. This is the stage where "There is nothing to do, yet nothing is left undone." The attainment of the Fourth Dhyana is merely necessary part of the process of developing skill in meditation. There is nothing extraordinary about it. Do not mistakenly think that you have already realized the fruition. If you have that idea, you would be making the same mistake as the Unlearned Bhikshu, and you could fall into hells.
四禅的境界，还是凡夫的地位。如果精进向前，证到“五不还天”的境界，才是证得圣人的地位。但此位尚未了生死，非得超出三界，才能了生脱死。这一点要弄清楚，不可混为一谈。
One who reaches the level of the Fourth Dhyana is still considered an ordinary person. If he continues to make vigorous progress and realizes the state of the Five Heavens of No Return, only then has he realized sagehood. Even so, he still hasn't put an end to birth and death. One must transcend the Triple Realm before one can end birth and death. This point must be made clear: different stages should not be mixed up.
