No matter what method you use -- buddho, rising & falling or samma araham -- when the mind is about to settle down in concentration, you won't be thinking that the mind is about to settle down, or is settling down, or anything at all. It will settle down automatically on its own. You won't even know when you let go of your meditation word. The mind will simply have a separate calm and peace which isn't in this world or another world or anything of the sort. There's no one and nothing at all, just the mind's own separate state, which is called the world of the mind. In that state there won't be the word 'world' or anything else. The conventional realities of the world won't appear there, and thus no insight of any sort will arise in there at all. The point is simply that you train the mind to be centered, and then compare it to the state of mind which isn't centered so that you can see how they differ, how the mind which has attained concentration and then withdraws to contemplate matters of the world and the Dhamma differs from the mind which hasn't attained concentration.
The heart and the mind. Let's talk some more about the heart and mind so that you'll understand. After all, we're talking about training the mind in concentration: If you don't understand the relationship between the heart and the mind, you won't know where or how to practice concentration.
Everyone born -- human or animal -- has a heart and mind, but the heart and mind have different duties. The mind thinks, wanders and forms ideas of all sorts, in line with where the defilements lead it. As for the heart, it's simply what knows. It doesn't form any ideas at all. It's neutral -- in the middle -- with regard to everything. The awareness which is neutral: That's the heart.
The heart doesn't have a body. It's a mental phenomenon. It's simply awareness. You can place it anywhere at all. It doesn't lie inside or outside the body. When we call the heart-muscle the heart, that's not the true heart. It's simply an organ for pumping blood throughout the body so as to keep it alive. If the heart-muscle doesn't pump blood throughout the body, life can't last.
People in general are always talking about the heart: "My heart feels happy... sad... heavy... light... down..." Everything is a matter of the heart. Abhidhamma experts, however, speak in terms of the mind: the mind in a wholesome state, the mind in an unwholesome state, the mind in a neutral state, the mind on the level of form, the mind on the formless level, the mind on the transcendent level and so on, but none of them know what the real heart and mind are like.
The mind is what thinks and forms ideas. It has to make use of the six senses as its tools. As soon as the eye sees a visual object, the ear hears a sound, the nose smells an aroma, the tongue tastes a flavor, the body comes into contact with a tactile sensation -- cold, hot, hard or soft -- or the intellect thinks of an idea in line with its defilements, good or bad: If any of these things are good, the mind is pleased; if they're bad, it's displeased. All of this is an affair of the mind, or of defilement. Aside from these six senses, there's nothing the mind can make use of. In the texts they are analyzed into the six faculties, the six elements, the six forms of contact, and all sorts of other things, but all these things lie within the six senses. So these are characteristics of the mind: that which can never sit still.
When you train the mind -- or, in other words, practice concentration -- you have to get control over the mind which is wriggling after the six senses, as already explained, and make it stop still with one thing: its meditation word, buddho. Don't let it go straying out ahead or behind. Make it stay still, and know that it's staying still: That's the heart. The heart has nothing to do with any of the six senses, which is why it's called the heart.
When people in general talk about the heart of something, they are referring to its center. Even when they talk about their own hearts, they point to the center of the chest. Actually, the heart doesn't lie in any particular place at all -- as I have already explained -- although it lies right in the center of everything.
If you want to understand what the heart is, you can try an experiment. Breathe in deeply and hold your breath for a moment. At that point there won't be anything at all except for one thing: neutral awareness. That's the heart, or 'what knows'. But if you try to catch hold of the heart in this way, you can't hold on to it for very long -- only as long as you can hold your breath -- but you can give it a try just to see what the true heart is like.
(Holding the breath can help reduce physical pain. People who are suffering from great pain have to hold their breath as one way -- fairly effective -- of relieving their pain.)
Once you realize that the heart and mind have different duties and characteristics like this, you'll find it easier to train the mind. Actually, the heart and the mind are really the same thing. As the Buddha said, the mind is identical with the heart. When we practice concentration, it's enough just to train the mind; once the mind is trained, that's where we'll see the heart.
Once the mind has been fully trained by using mindfulness to keep it with buddho as its only preoccupation, it won't go straying after different things, and instead will gather into oneness. The meditation word will disappear without your being aware of it, and you will feel a sense of peace and ease which nothing else can equal. Those who have never experienced this ease before, when they first experience it, won't be able to describe it, because no one else in the world has ever experienced that kind of peace and ease. Even though other people have experienced it, it's not the same. For this reason, you find it hard to describe -- although you can describe it to yourself. If you try to describe it to others, you have to use similes and analogies before they'll understand you. Things of this sort are personal: Only you can know them for yourself.
In addition, if you have developed a lot of potential in previous lifetimes, all sorts of amazing things can happen. For example, you may gain knowledge of heavenly beings or hungry ghosts. You may learn about your own past and future, and that of other people: In that particular lifetime you were like this; in the future you'll be like that. Even though you didn't intend to know these things, when the mind attains concentration it can know on its own in a very amazing way.
This sort of thing is something which really fascinates beginning meditators. When it happens to them, they like to brag to other people. When those people try to meditate, but don't get the knowledge or abilities, they become discouraged, thinking that they don't have the merit or potential to meditate, and they begin to lose faith in the practice.
As for those who see these sorts of things, when that knowledge or ability deteriorates -- because they've been carried away by external things, and haven't taken the heart as their foundation -- they won't be able to grab hold of anything at all. When they think of the things they used to know, their minds become even more stirred up. People who like to brag will take the old things they used to see and talk about them in glowing terms. Avid listeners really love to listen to this sort of thing, but avid meditators are unimpressed -- because true meditators like to listen only to things which are present and true.
The Buddha taught that whether his teachings will flourish or degenerate depends on those who practice them. The teachings degenerate when meditators get just a little bit of knowledge and then go bragging to other people, talking about external matters with no substance at all, instead of explaining the basic principles of meditation. When they do this, they make the religion degenerate without their even realizing it.
Those who make the religion flourish are those who speak about things which are useful and true. They don't speak just for the fun of it. They speak in terms of cause and effect: "When you meditate like this, repeating the meditation word in this way, it will make the mind gather into one and snuff out its defilements and restlessness like this...."
When you meditate on buddho, be patient. Don't be in a hurry. Be confident in your meditation word, and use mindfulness to keep the mind with its buddho. Your confidence is what will make the mind firm and unwavering, able to let go of all its doubts and uncertainties. The mind will gather in on its meditation word, and mindfulness will keep it solely with buddho at all times. Whether you sit, stand, walk, lie down, or whatever work you do, mindfulness will be alert to nothing but buddho. If your mindfulness is still weak, and your techniques still few, you have to hold on to buddho as your foundation. Otherwise your meditation won't progress; or even if it does progress, it won't have any foundation.
For concentration to be strong, the mind has to be resolute. When mindfulness is strong and the mind resolute, you decide that this is what you want: "If I can't catch hold of buddho, or see buddho in my heart, or get the mind to stay put solely with buddho, I won't get up from my meditation. Even if my life will end, I don't care." When you do this, the mind will gather into one faster than you realize it. The meditation word buddho, or whatever it is that may have been bothering or perplexing you, will vanish in the flash of an eye. Even your body, which you have been attached to for so long, won't appear to you. All that remains is the heart -- simple awareness -- cool, calm and at ease.
People who practice meditation really like it when this happens. The next time around, they want it to happen again, and so it doesn't happen again. That's because the desire keeps it from happening. Concentration is something very subtle and sensitive. You can't force it to be like this or that -- and at the same time you can't force the mind not to enter concentration either.
If you're impatient, things get even more fouled up. You have to be very patient. Whether or not the mind is going to attain concentration, you've meditated on buddho in the past, so you just keep meditating on buddho. Act as if you had never meditated on buddho before. Make the mind neutral and even, let the breath flow gently, and use mindfulness to focus the mind on buddho and nothing else. When the time comes for the mind to enter concentration, it will do it on its own. You can't arrange the way it will happen. If it were something you could arrange, all the people in the world would have become arahants long ago.
Knowing how to meditate, but not doing it right; having done it right once, and wanting it to be that way again, and yet it doesn't happen: All of these things are obstacles in practicing concentration.
In meditating on buddho, you have to get so that you are quick and adept. When a good or a bad mood strikes you, you have to be able to enter concentration immediately. Don't let the mind be affected by that mood. Whenever you think of buddho, the mind gathers immediately: When you can do this, your mind will be solid and able to rely on itself.
When you have practiced so that you are adept and experienced in this way, after a while you will find that your defilements and attachments to all things will gradually disappear on their own. You don't have to go clearing away this or that defilement, telling yourself that this or that defilement has to be removed with this or that teaching or this or that method. Be content with whatever method you find works for you. That's plenty enough.
To have the defilements gradually disappear with the method I've just explained is better than trying to arrange things, entering the four levels of absorption, sustained thought, rapture and pleasure, leaving just one-pointedness and equanimity; or trying to arrange the first stage of the path to nibbana by abandoning self-identity views, uncertainty and attachment to precepts & practices; or by looking at your various defilements, telling yourself, "With that defilement, I was able to contemplate in such-and-such a way, so I've gone beyond that defilement. I have so-and-so many defilements left. If I can contemplate in such-and-such a way, my defilements will be finished" -- but you don't realize that the state of mind which wants to see and know and attain these things is a defilement fixed firmly in the mind. When you finish your contemplation, the mind is back in its original state, and hasn't gained anything at all. On top of that, if someone comes along and says something which goes against the way you see things, you start disagreeing violently, like a burning fire into which someone pours kerosene.
So hold firmly to your meditation word, buddho. Even if you don't attain anything else, at least you've got your meditation word as your foundation. The various preoccupations of the mind will lessen, or may even disappear, which is better than not having any foundation to hold to at all.
Actually, all meditators have to hold firmly to their meditation word. Only then can they be said to be meditation with a foundation. When their meditation deteriorates, they'll be able to use it as something to hold to.
The Buddha taught that people who make the effort to abandon defilement have to act like old-time warriors. In the past, they'd have to build a fortress with strong walls, moats, gates and towers to protect themselves from enemy attack. When an intelligent warrior went out to battle and saw that he was no match for the enemy, he would retreat into his fortress and defend it so that the enemy couldn't destroy it. At the same time, he would gather enough troops, weapons and food (i.e., make his concentration forthright and strong) and then go out to resume his fight with the enemy (i.e., all the forms of defilement).
Concentration is a very important strength. If you don't have concentration, where will your discernment gain any strength? The discernment of insight meditation is not something that can be fashioned into being by arrangement. Instead, it arises from concentration which has been mastered until it is good and solid.
Even those who are said to attain Awakening with 'dry insight': If they don't have any mental stillness, where will they get any insight? It's simply that their stillness isn't fully mastered. Only when we put the matter this way does it make any sense.
When your concentration is solid and steady to the point where you can enter and leave it at will, you will be able to stay with it long and contemplate the body in terms of its unattractiveness, or in terms of its physical elements. Or, if you like, you can contemplate the people of the world until you see them all as skeletons, or you can contemplate the entire world as empty space....
Once the mind is fully centered, then no matter whether you are sitting, standing, walking or lying down, the mind will be centered at times. You will be able to see clearly how your own defilements -- greed, anger and delusion, which arise from the mind -- arise from this and that cause, how they remain in this or that way, and you will be able to find means to abandon them with this or that technique.
This is like the water in a lake which has been muddy for hundreds and hundreds of years suddenly becoming clear so that you can see all the things lying along the lake-bottom -- things which you never dreamed were there before. This is called insight -- seeing things as they truly are. Whatever sort of truth they have, that's the truth you see, without deviating from that truth.
Forcing the mind to be still can make it let go of defilement, but it lets go in the same way a person cuts grass, cutting just the part above ground, without digging up the roots. The roots are sure to send up new shoots when rain falls again. In other words, you do see the harm of the preoccupations which arise from the six senses, but as soon as you see it, you retreat into stillness without contemplating those preoccupations as carefully as you do when the mind is in concentration. In short, you simply want stillness, without wanting to spend any time in contemplation -- like a ground lizard which relies on its hole for safety. As soon as it sees an enemy coming, it runs into its hole, escaping danger only for a while.
If you want to uproot your defilements, then when you see that defilement springs from the six senses -- for instance, the eye sees a visual object or the ear hears a sound, contact is made which causes you to be pleased or displeased, happy or sad, and then you grasp onto it as your preoccupation, making the mind murky, disturbed and upset, sometimes to the point where you can't eat or sleep, and can even commit suicide -- when you see this clearly, make your concentration firm and then focus your mind exclusively on examining that particular preoccupation. For instance, if the eye sees an attractive visual object which makes you feel pleased, focus on examining just that sense of pleasure, to find out whether it arises from the eye or from the visual object.

If you examine the visual object, you see that it's just a physical phenomenon. Whether it's good or bad, it doesn't try to persuade you to be pleased or displeased, or to make you love it or hate it. It's simply a visual object which appears and then disappears in line with its own nature.
When you turn to examine the eye which sees the visual object, you find that the eye goes looking for objects and, as soon as it finds one, light gets reflected into the optic nerves so that all kinds of visible forms appear. The eye doesn't try to persuade you to be pleased or displeased, to love or to hate anything. Its duty is simply to see. Once it has seen a visible form, the form disappears.
As for the other senses and their objects, attractive or unattractive, they should be examined in just the same way.

When you contemplate in this way, you will see clearly that all the things in the world which become objects of defilement do so because of these six senses. If you contemplate the six senses so that you don't tag along after them, defilements won't arise within you. On the contrary: Insight and discernment will arise instead, all because of these same six senses. The six senses are the media of goodness and evil. We will head for a good or a bad destination in the next life because of the way we use them.
The world seems broad because the mind isn't centered, and is left free to wander among the objects of the six senses. The world will narrow down when the mind has been trained in concentration so that it lies under your control and can contemplate the six senses exclusively within it. In other words, when the mind is fully concentrated, the outer senses -- the eye seeing forms, the ear hearing sounds and so on -- won't appear at all. All that will appear are the forms and sounds which are mental phenomena present exclusively in that concentration. You won't be paying any attention to the outer senses at all.

When your concentration is fully solid and strong, you will be able to contemplate this world of the mind which gives rise to sensory contact, perceptions, preoccupations and all defilements. The mind will withdraw from everything leaving just the heart, or simple awareness.
The heart and the mind have different characteristics. The mind is what thinks, forming perceptions and preoccupations to the point of latching on holding them to itself. When it sees the suffering, harm and stress which come from holding onto all the defilements, it will go and withdraw from all preoccupations and defilements. The mind will then be the heart. This is how the heart and mind differ.