Some meditators think that they have to visualize as clearly as when the eye perceives something. However, the object will not be so clear, since it is not the eye that meditates. The eye consciousness is thought-free. It is not in the least able to meditate on a deity. It merely perceives what is in its sight, but it cannot “visualize” as such. It is the mind consciousness that visualizes the deity. While the mind consciousness is meditating there is no real external object, as is the case when the eye perceives forms. Nevertheless, there is a kind of image of the object that appears to the mind consciousness. This image is created by the mind itself. As soon as the mind wavers, the object that it has created will change as well and at once be unstable. That’s why we cannot visualize clearly while the mind is unstable. When the mind becomes more stable it is able to keep the self-created appearances longer. When the mind creates the appearance of a deity freshly and is not stable while doing so, this appearance will almost immediately vanish as soon as it arises. If the mind is a bit more stable, however, this reflection will remain for much longer. Whether the visualization of the deity in our meditation is clear or not depends solely on the stability of our mind. And this is exactly what we are training in when we meditate on a deity.
In the meditation on calm abiding also, it is not the five sense consciousnesses that meditate, but the mind consciousness. Some practitioners believe that when they constantly see objects with their eyes while meditating on calm abiding, their meditation is impaired, or that when they perceive sounds with their ears, their meditation will not be that beneficial. However, the five sense consciousnesses are not in the least able to create anything; therefore they cannot distract our mind either. The eyes indeed see forms, but it doesn’t matter. Likewise the ears hear sounds, and the nose perceives smells, yet this does not disturb the meditation in the least, because the sense perception does not involve any thoughts. It is only a matter of mere appearances. This is the reason why we do not have to stop them. We would not even be able to stop them, nor do we have to modify anything in any way. The sense perception just happens naturally, by itself.
Then what is it that we have to do? While the mind consciousness meditates on calm abiding, it moves wildly. In moving it remembers the past, thinks ahead of the future, or finds itself within the present. It is shaken by many different thoughts: thoughts of happiness, thoughts of suffering, and many other kinds. When the mind does not continuously change in this way, but has instead become stable and is able to rest within itself, then it can be said that we remain within the meditative concentration of calm abiding.
Now, there are some skeptical persons who may think that when the mind is not moved by many thoughts, it will be in a stupid state. But stupidity does not arise just because the mind relaxes a little. On the contrary, the mind usually thinks too much. We are used to thinking uninterruptedly and continuously. If we look at these thoughts more closely, however, we discover that we seldom think meaningfully at all, and that most of our thinking is rather senseless. Such senseless thinking happens frequently and repeats itself over and over. In this way our many endlessly occurring thoughts are continuously going around and around in circles. If we are able to decrease this senseless thinking, meaningful thoughts will naturally increase all by themselves. And this is exactly the reason for the meditation on calm abiding: when the mind relaxes, senseless thinking will effortlessly diminish.
All of the six consciousnesses apprehend objects; therefore they are also called the “six apprehending consciousnesses.” The five sense consciousnesses apprehend their respective objects directly, whereas the mind consciousness apprehends these indirectly and allows thoughts to arise. Thus the most important consciousness by far is the mind consciousness. It acts as the root for all attachment and aversion, all happiness and suffering. Thus it is as important for our daily life as it is for our meditation. For it is only the mind consciousness that can meditate. In the context of the three activities of Buddhist practice—namely listening, reflecting, and meditation—the mind consciousness plays the largest part. “Listening” happens immediately after the arising of an ear consciousness which itself merely perceives the sounds of the words but which cannot itself connect the sounds to any meaning. “Reflecting” about the meaning of the words is undertaken solely by the mind consciousness, which is also responsible for “meditating,”
Thus the six collections of consciousness constitute two different categories of consciousness, each with different defining characteristics. There are the five sense consciousnesses that clearly perceive and have direct contact with the object. And then there is the mind consciousness that merely perceives its own self-created images of these objects, and therefore these objects appear as vague, wavering, or unclear.
Another difference between the five sense consciousnesses and the mind consciousness concerns time. The sense consciousnesses can only perceive in the very present moment, whereas the mind consciousness can think about the past, the present, and the future. Buddhist scholars use the following simile: “The five sense consciousnesses are like a mute with good eyes.” They perceive clearly, but are not able to express themselves or to ‘talk’ about what something actually looks like nor what indeed it is that they perceive. The quote continues: “The thoughts are like blind persons who are gifted speakers.” This refers to the mind consciousness which, although it only perceives the objects in a vague and unclear way, “talks” a lot about them, commenting with its many thoughts on the vaguely perceived objects like a well-gifted speaker.