I believe there are many people who do not know exactly what Yin and Yang are. To explain it, I would have to refer to Oriental philosophy where these concepts find their roots.
Oriental philosophers traditionally divide the energy of the Universe into two conflicting sources Yin and Yang. The infinity of the Universe is resolved into two sources, and their conflict turns into physical, material vibrations that create energy, the energy somehow turns into elementary particles, then elements. When elements are assembled together they give life to plants, which evolve into animals and eventually into humans. That is the idea of the ancient Chinese thinkers.
2500 years B.C. Chinese philosopher Futsugi divided all phenomena into eight groups, or ke, and named the infinity of the Universe taichi. According to is theory, in the beginning there was only taichi, a whole, which then was divided into Great Yang (the Sun) and Great Yin (the Moon). These were consequently divided into halves, and the process went on until there were eight concepts, or groups.
Another famous Chinese, Roshi, went further and developed his own theory of the paths of virtue, based on the Futsugis ideas. It claims that one path makes two, two paths make three, and three paths create everything. In other words, everything in this world has the heart of Yang inside and the covers of Yin outside. These two powers create an active balance, a harmony vibrant with power.
Indian schools of philosophy, for example Vedanta, echo this theory. Vedanta says that in the beginning of all the only God Brahma created two gods, the god Shiva and the goddess Shakti. It proves that the concept of dual unity is fundamental for Oriental philosophy and medicine.
This concept can be also found in the works of a great Western philosopher, Einstein, who created the theory of relativity, sensing with his sixth sense the existence of the two conflicting world, matter and energy. He said that matter always creates energy, and energy turns into matter. He proved that the balance of Yin and Yang is not as mysterious and strange as people had tended to think before him.
