In this connection let me tell you a story from my own experience as a preacher. It is about a meditator from my native village Hseipkhun in Shwebo district. He was none other than a cousin of mine. He was one of the first three persons to take up insight meditation in the village. The three of them agreed among themselves to work for a week first. They worked very hard. They had brought to the hermitage cigars and betel quids to be taken one each day. But when they returned from the hermitage they took home all the seven cigars and betel quids - untouched.
So hard did they work that in three days they attained the knowledge of rising and falling and were overjoyed to experience tranquility and see brilliance around. "Only at this old age have we discovered the truth," they spoke with great joy. Because they were the first to take up meditation I thought of letting them go with their joys and just told them to go on noting. I did not tell them not to note the joys, So, although they worked for four more days, they did not get any higher.
After a few days' rest they came again for another week of meditation. That cousin of mine then reached the stage of the knowledge of dissolution. Although he was noting 'rising, falling, sitting,' he did not see the abdominal shape, and his body seemed to have disappeared, so he had to touch it with his hand to see if it was still there, he told me. And, whenever he looked or saw, everything seemed to be dissolving and breaking up. The ground he looked at was dissolving, and so were the trees. It was all against what he had thought things to be. He began to wonder.
He had never thought such external, season-produced, gross material things like earth, trees, logs, etc., could be incessantly breaking up. He had thought they perished only after a considerable length of time. They lasted for quite a long time, he thought. Now, as insight knowledge gained momentum with meditation, the rising and passing away of phenomena appeared to him of their own accord without his specially meditating on them. They were passing away, breaking up, there before him. It was all the reverse of his former beliefs. Perhaps his new vision was wrong. Perhaps his eye sight was failing.
So he asked me. And I told him. The passing away and breaking up he saw in everything were true. As your insight grew sharper and quicker, things appear rising and passing away to you without your meditating on them. These are all true. I explained to him. Later on he again told me about his own findings as he progressed in insight. Today he is no more. He has long been dead.
When insight knowledge has grown really sharp, it will prevail over wrong beliefs and thoughts. You see things in their true light, as impermanent, suffering, not-self. An uncultured mind or reflection without meditation cannot give you real insight into the nature of things. Only insight meditation can do that.
Once you realise impermanence, you see how they oppress you with their rising and passing away, how you can derive no pleasure from them, how they can never be a refuge, how they can perish any moment, so how they are frightening, how they are sufferings, etc.
" ... ill (suffering) in the sense of fearful."
You thought, "This body will not perish so soon. It will last for quite a long time." So you took it for a great refuge. But now as you meditate you find only incessant risings and passings away. If no new ones rise up for the mental and material things that have passed away, one dies. And this can happen any moment. To make a self out of these mental and material things that can die any moment and to take a refuge in it is as dreadful a thing as sheltering in an old tumble-down house.
And you find that nothing happens as you desire. Things just follow their natural course. You thought you could go if you wished to, sit if you wished to, rise, see, hear, do anything if you, wished to. Now as you meditate you find that it is not so. Mind and matter are found to be working in a pair. Only when there is intention to bend is there the form bending. Only when there is intention to stretch is there the form stretching. There is effect only when there is cause. Only when there is something to see do you see. If there is something to see, you can't help seeing it. You hear when there is something to hear. You feel happy only when there is reason to be happy. You worry when there is cause to worry. If there is cause, there is effect. You cannot help it. There is no thing that lives and does what it desires. There is no self, no ego, no I. Only processes of arising and passing away.
To understand clearly is the most important thing in insight meditation. Of course, you will come across joys, tranquillities, bright lights in the course of your training. They are not important things. What is important is to understand impermanence, suffering and not-self. These characteristics are made clear to you as you just keep on meditating as explained.