Yin Yang Theory: The Dance of Light and Shadow

At the heart of Chinese Medicine lies the ancient theory of yin yang. More than a system of categorization, the theory is an explanation of the nature of relationships, patterns and change.

The original Chinese character for yin meant something close to the shady side of a slope. Yin is associated with qualities relating to that shady side – coolness, shadow, downwards movement and by extension – interiority, receptivity, tranquility, stillness and completion.

The character for yang, on the other hand, meant the sunny side of a slope. The idea embodied light, brightness, upward movement and stretched to include ideas of dynamism, exteriority, arousal, and beginnings.

Classical thought went on to develop five principles associated with yin and yang. This began with the idea that all things had a yin and a yang facet that could be broken down into yin and yang again and again. Yin and yang were seen to mutually create each other, mutually control each other and mutually transform into each other. They formed a perfect, perfectly shifting universe where one became the other before turning back into itself again.  

Yin yang theory can be applied to natural cycles like the course of a day, where midnight is the time of deepest yin and midday the time of maximum yang – the hours and minutes in between, the falling of one state into the other.

Yin yang theory also works with the cycle of the year, with midwinter the time of fullest yin and midsummer, the time of most potent yang. By living in accordance with the natural cycles of the world we support our health and well-being.

As Dr Daniel Keown states in his fascinating book The Spark in the Machine – How the Science of Acupuncture Explains the Mysteries of Western Medicine the dance of yin and yang is at the very heart of conception. Sperm couldn’t be more yang – fast moving and short-lived, whereas an egg is essentially yin – drifting without means of direction and accepting whatever penetrates it. And yet these two very separate states create the basis of life as we know it.

From the yang top of our heads to the yin soles of our feet, from the soft fronts of our bellies to the muscular arcs of our backs we walk, live and breathe the continuous dance of yin becoming yang becoming yin again.

The Chinese Classic, the Huang Di Nei Jing Su Wen tells us that yin and yang are the way of sky and earth. Fundamental to all things, they are the parents of change and transformation, the origin and beginning of birth and destruction and, as such, they are necessary in understanding the basis of treating disease.

If we learn how to cultivate yin through food, rest and meditation, if we understand how to generate yang through diet, movement and action, we have within our grasp the essential elements to heal ourselves. And, beyond that, to create a world around us in which we can thrive.