as complementary aspects of the whole. Fu His formulated two symbols to
represent this idea: a broken line and an unbroken line. These symbols
depicted the two major forces in the universe – creation and reception – and
how their interaction formed life. This duality was named yin–yang and
represents the foundation of Chinese medicine. Thus, the meaning of night
is linked to the meaning of day, the ebb of a tide to the flow, and hot with
cold. Perhaps the most appropriate link might be that of health and disease,
often thought of as being direct opposites. A different view might be that
these are both facets of life, each necessary for the other, indeed each giving
rise to the other.^8 Thus disease may be thought of as a manifestation of
health.
The relationship between the two elements is dynamic: nature constantly
moves between the two. An analogy might be provided by considering a cup
of coffee that starts as yang; as it cools the yang changes to yin, passing
through an equilibrium that is just right for drinking. At any stage the appli-
cation of heat will cause a flow back into yang. This element of change
involving energy flows (see below) is seen as a fundamental quality of life.
Yin and yang are now reflected in the well-known entwined symbol (the
tai ji symbol), depicted in Figure 6.1. Thus:
- Yin is a negative state associated with cold, dark, stillness and
passivity: its symbol can be represented by the dark side of a mountain. - Yang is a positive state associated with heat, light and vigour: its
symbol can be represented by the sunny side of a mountain.
An example of the yin–yang principle in therapeutics may be provided
by considering a patient who has a fever, i.e. an excess of yang. Only when
the opposites are in equal balance is life in harmony. Too much or too little
of either element results in disharmony. Treatment would therefore be seen
as the ability to promote the conversion of excess yang into yin, allowing
restoration of the equilibrium between the two and a consequent resolution
of the fever.
As the organs of the body were
discovered they were deemed to be yin
or yang. Yang organs, including the
heart, spleen, lungs, kidneys and liver,
are hollow and normally referred to as
the ‘fu’, whereas yin organs, including
the stomach, intestines and bladder, are
solid and referred to as ‘zang’.^9 Each
organ also has a yin and yang element
within it, and it is the overall imbalance
that leads to disease.
122 | Traditional medicine
Figure 6.1 Yin and yang symbols.