2.   The way to true understanding is jori. The key to jori is simply discarding habits of thought, following the correct signs, and seeing opposites as one.

Discarding habits of thought means freeing oneself from personal attachments.

Following the correct signs means being able to distinguish those things that are signs from those that are not. For example, as we see it, there is every sign that the sun and moon travel westwards, but the truth is they travel eastwards, and water seems certainly to be the enemy of fire, but fire in fact depends on water.

The way of heaven-and-earth is yin and yang. The bodies of yin and yang contrast and oppose one another, and by opposition they combine as one. Then they constitute heaven-and-earth.

Because opposites unite as one, when we look at things as opposites and also as one we are seeking their true nature. Jori signifies that one possesses two, and two open one. When there are two, their distinctness reveals jori, when there is one, the two merge and no seams are visible. Seeing opposites as one is the art of discovering things in this way.

If we cannot see opposites as one, we cannot perceive yin and yang, if we cannot perceive yin and yang, even those of us who are most wise and well-informed are unable to see into the innermost recesses of heaven-and-earth. This is why we also call jori "the key to the gates of heaven".

"Jo" originally meant a branch of a tree, and "ri" referred to the grain of the wood.

Take the example of a tree. A tree-trunk has roots below and branches above. The roots gradually divide into more roots, and the branches into more branches. If you look closely at the points where they divide you will find lines of the grain of the wood. What is the purpose of these lines? They are there for the ki that is conveyed along them, and the grain determines the pattern in which the ki is conveyed.

Water is another example. Channels must be made to convey water through the fields. These channels are the ri of the water. The ri divide into branches. A thousand branches may become ten thousand branches, but because of ri, even if the fields were endless, water would reach the millions of leaves of rice there, to the tips of the grains, by flowing in along the ri.

The ki of heaven travels from east to west, and the sun and moon in the reverse direction. Rivers run and tides flow, kites fly and fishes leap; and in all of these ki is conveyed according to their ri. To see this, pick a green leaf and look at its veins. The larger ri divide into finer ri, and the ri continue thus until they are so fine they are no longer visible. The ki that is conveyed along these ri forms the different shapes of the leaves. ri form the shapes of all things by conveying ki; from heaven and earth, seas and mountains, to all the kinds of birds, fish, turtles, worms and fungi. There can be no ri that do not convey ki.

Although the "ri" of "jori" bears some relation to that word as it was used by the ancients, our usage here is as different from theirs as the living are from the dead. The arteries and veins of the human body are these ri and nothing else. Insofar as ri are found in things with shape, it is these ri which determine whether they be beautiful or ugly, long or short. However, because people are so accustomed to things they do not persist in enquiry, their interest in the human body does not extend beyond the pulses. They take the words of Wang Shu Ho as the direct pronouncement of a creator, as the Golden Rule, and their small minds see the slightest hint of doubt as an obstacle to enlightenment. All their lives they hold fast to the frantic confusion of the Ming Hall and never find what they seek.

Arteries and veins are the routes by which ki and blood are conveyed through the body, and it is within these that ki and matter are separated. Although the ancients had names for arteries and veins, they did not try to give a clearer account of them. Instead, they contented themselves with the familiar, stuck to their books, and failed to see the correct signs. As these words were invented by holy men they were revered as the pronouncements of a creator.

In other words, instead of taking heaven-and-earth as their teacher, the ancients made the mistake of taking men as their teachers. Taking heaven-and-earth as teacher is using the method of looking for opposites, and once we have mastered the art of seeing opposites we shall not accept anything as fact that is not true of heaven-and-earth. However remote, obscure, deep or mysterious, if anything exists in heaven and earth it can be thought about.