TCM understands that everything is composed of two complementary energies, one is Yin and Yang is the other. They are never separated, one can not exist without the other. This is the principle of Yin and Yang of the interconnection and interdependence, there is no opposition. The relationship is reflected in the interlaced black and white classic Yin and Yang. No matter how you might try to divide the circle into two, the two sections always contain both energies. The energies themselves are indivisible. From the viewpoint of TCM, it is the simplest and most profound universal law.
The theory of Yin and Yang contains no absolute. The designation of something as Yin or Yang is always on, or in comparison with something else. For example, the sun and day are considered Yang versus the moon and the night, which are Yin. However, early in the morning is considered Yang compared with the late afternoon, which is more Yin. According to the theory of Yin and Yang, all that is masculine is Yang and all that is female is Yin. Everything in the body is also under the control of the binary system of Yin and Yang. Because Yin and Yang have an inseparable relationship, if there is a problem with one, the other will certainly be affected.
Ideally, Yin and Yang must always be in harmony, not only in equilibrium. Understanding harmony is an important aspect of TCM. Often, understanding in the West of complementary and alternative medicine, the term “balance” is described as the desired state, however, in Traditional Chinese Medicine, “harmony” is the ultimate goal. Although the words “balance” and “harmony” are sometimes used interchangeably, in TCM theory they are very different: the balance is simply the first step toward harmony. Two things can be balanced, they can be of equal proportion, or have equal weight, and yet still be separated. This has to do with the relationship between two separate entities: for example, the relationship between the heart and kidneys. First, a relationship must be balanced, the next step is to achieve harmony. When two things are in harmony, their energies are not only as proportionate, but blended together into a coherent whole. When two elements exist in harmony, this is an ongoing process, an unconscious dance between them that occurs naturally. When one dominates the other retreats, internal harmony is a dynamic state. In a healthy system, harmony occurs naturally in the body itself and between the body and the external forces of Nature and the Universe. Thus, when the Qi of nature is changing, as is the case for seasonal variations, the internal Qi of a person will respond automatically. If for some reason he can not make a smooth transition to the energy of the next season, TCM understands that this will cause the disease.
In Western medicine, this lack of harmony can be seen in patients with hot flashes. Those who suffer from this condition during the day have a Yang Qi or energy deficiency, those who suffer from hot flashes at night are experiencing a shortage of Yin Qi. If a woman is experiencing hot flashes at the two times, the two energies are weak and need strengthening.