Because non-living things cannot replicate themselves, non-living things under natural conditions are simple and have no complex structures. Because complex structures, once created, quickly become extinct, the evolutionary process always starts from beginning. This is the essential difference between living things and non-living things.

Like the race between tortoise and the hare, the tortoise runs slowly, but keeps running. Organisms evolve slowly at first, but after billions of years of continuous evolution, they are completely different from non-living things.

Therefore, the essential difference between living things and non-living things is self-replication, and those that can self-replicate are living things, and those that cannot self-replicate are non-living things. In Chinese, “to live”is called “Sheng Huo(生活)”. “Sheng”means giving birth to children, which is self-reproduction. "Huo" means to be alive. Just because we can give birth, then we are alive, if we can't give birth, then we are not alive. This is “Sheng Huo(生活)”. 

3.2 The Essence of Human

The secret of human civilization is also replication, because the rich ideas of mankind are constantly accumulated on the basis of replication. People are more advanced than animals, because the human brain is more complex and ordered, so the human mind is more complex and ordered.

Many people think that creativity is an essential characteristic of human beings, which is wrong. Animals can be creative, too. Chimpanzees, for example, make simple tools by stripping leaves off branches and sticking branch into holes to bring ants out. It's even possible to make more complex tools.

We can imagine that a monkey once discovered how to use fire, how to keep fire. In the course of millions of years of evolution, this kind of thing is entirely possible. But when this monkey died, this skill was lost. Because this ability is an acquired trait, it cannot be inherited through biological genes. So civilizations created by animals always started from scratch, and it could take hundreds of years for the monkey's descendants to recapture the discovery, found it, and then quickly lost it and started all over again. Hundreds of thousands of years later, their civilization was still at its origin, while human civilization had taken off.

Why could human civilization take off? The fundamental difference between human and animal is that human acquired traits can be inherited. How to inherit? It is to inherit the wisdom of predecessors through acquired learning. So human civilization can accumulate from generation to generation. Not afraid of slow, afraid of standing, after hundreds of thousands of years of continuous evolution, people and animals have a world of difference.

Therefore, human being is an animal that lives mainly on inherited acquired traits. Words and symbols are memes or cultural genes.

The acquired traits of human include human rationality, logical thinking, sociality, creating and using tools and so on. These are acquired human traits. What's more, memes are copied so fast -- newspapers can make millions of copies a day -- that humans evolve much faster than animals.