"Tao generates one, one generates two, two generates three, three generates all things" comes from Chapter 42 of Laozi's "Tao Te Ching", which is Laozi's theory of the creation of the universe. Here Lao Tzu talks about "one", "two" and "three", which refers to the process by which "Tao" creates all things. It mainly talks about the numbers one, two and three, but does not regard one, two and three as specific things and specific quantities. They just represent the process by which "Tao" generates all things from few to many, from simple to complex. "Huainanzi Tianwenxun" is the earliest philosophical explanation of it so far: "Tao (called regulation) starts from one, and one does not come into being, so it is divided into yin and yang, and yin and yang combine to make all things come into being." . Therefore it is said: Two gives birth to two, two gives birth to three, and three gives birth to all things.” According to the explanation of "Huainanzi", "two" means "yin and yang", and "three" means "the harmony of yin and yin".