Cornerstone of today's science is a postulate that each must have its plus minus. This is true for both positive and negative electrical charges, opposite poles of a magnet for both left and the right spin of atomic particles, matter and antimatter, and for a myriad set of mathematical principles. Without binary math, which reduces everything to a chain of switches "turned on – off", there would be no computers, no digital recording, no TV. Someone might say that the small loss, but without the switch "turned on – off" in the neural circuits in our brain and we think something might not. It is a pity that the words positive and negative came to mean "good" and "bad" – such as "positive for someone to treat" and "negative character". In this book, for example, I will mention "the positive qualities," meaning the quality of design in opposed to "negative" in the sense that the first useful, and the last is not.
But in physics terms positive and negative, this is just an expression, allowing designate things that are opposite reaction. When we talking about positive and negative poles of the battery, we do not mean that one of them good and another bad. Likewise, the terms yin and yang are simply the equivalent definitions of opposite qualities without equating to one of them to "good" and another to "evil." This is the inner meaning of the terms yin and yang. They are interrelated and, ideally, vzaimouravnovesheny. Strictly speaking, Yin – is the absence of Yang.