According to a Chinese theory, there are two natural, complementary, and contradictory forces in our universe. These forces are different, but in the best way, they mutually complement each other.
Yin (Female): The passive, negative force. Yin is dark. She is docile, soft and slow, yet consuming and cold.
Yang (Male): The active, positive force. Yang is bright. He is dominant, hard, restless, producing and hot.
Although Yin and Yang are opposing forces, neither can Be without the other, similar to the way one cannot conceive Love without Hate, or Hate without Love.