Suzuki read a rendition of Joshu's Mu. He said Joshu began serious study, including travel and visits to various masters, after the age of 60. Before that he spent most of his time caring for his old Zen teacher.

Does a dog have buddha nature? Everyone knows that buddha nature is everywhere and includes everything. But if we all are buddha, why practice zazen? Consider the air. It too is everywhere, but until we use a fan, we are not aware of it. Zazen may be likened to the fanning. However, awareness of buddha nature, or the solution to mu are not our only problems. So there is no need to be narrowly over-concerned with what buddha nature refers to. You should not strain too hard to know what Zen is. One cannot study Zen in the usual manner. The way to study Zen is to be always aware of yourself, to be careful, to be sincere with yourself. Awareness means that when reading, your mind should not get caught by any idea. It should remain open. Similarly with sights and sounds, don't allow your mind's self-awareness to get lost or absorbed. In other words, always remain conscious of what you are doing, of what is going on. In all our activities we should have inward eyes. This is especially so during physical actions. When we are reading or thinking, our minds are not as full of activity. When we are involved in physical activity, then the mind is at full operation -- it is open. When we are thus attentive and one with our activity, we can deepen our understanding. When we practice this way, everything that happens is within our mind and everything we are involved in is the content of our practice. Such awareness of body-mind means that sounds, for example, arise from within the mind. Here there is no duality. Big mind arises when practice is within yourself - Zen conduct is occurring when there is no duality.

Though most people desire birth and avoid death, if death is included in our non-dualistic body-mind, then it cannot be an outside occurrence which we need fear. Death is not something outside of us.

In Zen practice, mountains are not over there, but instead are here within our mind. If we pursue such practice continuously, action and non-action are not distinct phenomena. When our mind is a river, the whole world is a river. When this non-arising of outside phenomena is attained, inflexibility is cast off. When we feel that phenomena is outside of us, then the mind loses its flexibility. When mind includes all things, then it is big and flexible. The various things we are aware of are temporary forms and colors of our mind.

[From Dogen]-- Those who study Zen can gain awakening if they reflect on themselves at the halfway mark. And we should not stop when we have attained enlightenment. “Do not stop when you have it.” This means that when the mind is constantly active in various ways, we are then enlightened. The instant we believe or say the idea that we are enlightened, at that instant our mind stops, freezes, no longer is open. So we have it as long as we are open. Thus when we have it we should not stop, or enlightenment ends and becomes a static impurity.

Even though we should not be caught by the ideas of Buddhism, there are plenty of good reasons for studying it. The Zen way is to know ourselves through and through, each moment to moment.

Questions

Buddhist understanding of body and mind is as two sides of one reality.

Buddhism is not essentially a philosophy, and hence is not primarily concerned with questions such as the origin of the world, what the soul does after death, when the end of earth will occur, and so forth. This is to be concerned as per the parable of the man shot with the poisoned arrow.

If someone insists on a philosophical and metaphysical discussion, Buddhism does have concepts which have developed from experience. It can present such kinds of support for its views. But after a certain point Buddhists will say we don't know or your questions are beyond the limits of intellectual and verbal faculties.

In discussing truths, Buddhists do not limit themselves to so-called objective facts. instead they always seek to include the subjective, the human. This is in distinction to the general attitude of Western science.

However, segments of Western science are coming closer to Buddhist notions of reality.

When movement stops, there is material. But where movement exists, it cannot be really considered a thing and hence it cannot be caught. So, since we cannot catch it, we follow it.

There is no more or less enlightenment - water is the same for large or small fish.

We must practice in enlightenment before we can attain enlightenment. This means we must move in partial defilement while we start and try to practice. It is natural, though faulty, for people to try to know the limits of sky and water before moving in it.