Copying is an imitation. For example, the teacher taught us to learn bodybuilding exercise. We imitate the teacher's actions. In the classroom, teacher writes on the blackboard, we copied it in our paper. This is also imitation. All education and publicity processes are imitation.

Animals can also create civilizations. We can imagine that if a monkey knows how to use fire, and knows how to keep the fire. So it can protect itself with fire and eat cooked food. But after the monkey died, this skill was lost. This skill is acquired character and cannot be inherited by biological genes. Even if the monkeys around can learn, if this group of monkeys extincts in a disaster, then this ability will be lost. The fundamental difference between humans and animals is that human acquired characters can be inherited.

Various skills and techniques of human beings are often lost, but if written on paper, they can be saved and passed to descendants. Therefore, animals cannot create civiliza- tions. Only humans can create civilizations. It doesn't matter how slowly you go as long as you don't stop. Animal's acquired characters are always lost, and human acquired characters can be inherited stably. If the libraries are destroyed, civilization will be degraded for thousand years.

Animals can also imitate simple things, but animals haven't invented words. The imitation by words is most efficient. Therefore, the invention of words is a sign of human civilization. All kinds of human thoughts and all science and technology are acquired characters. They cannot be inherited through biological genes but can be inherited through cultural genes. Various symbols such as word, audio and video are cultural genes, and the cultural genes make the acquired characters capable to be inherited.

Definition: Human being is a kind of animal that survive mainly on acquired characters such as science, technology, art and culture, which can be inherited.

Science must be inherited first, and then it can develop. If you do not study, when you want to invent, you can only step on other people's footprints. Learning is imitation, which is the reproduction of ideas. The essential difference between human and animal is that human can learn. This is called learning to be human.

There are many kinds of social theories, which always debate. When physics can grasp the whole universe, there is no social theory that can grasp the whole society. There is no social theory that proposes a decent model for the whole society. The proposal of cultural gene has finally made it possible for people to realize this expectation because it is comprehensive and simple. Being simple is the basic principle of theory. Biological genes are very simple compared to biological traits. Cultural genes should also be very simple compared to social reality. At the same time, cultural genes can fully reflect social life and human civilization, just as biological genes can fully reflect biological traits and evolution.

Another value of cultural genes is that social theory can be more inspired by biology. Compared with social theory, the level of development