Generally speaking, war is a collection of two problems. The first is the living space. The second is the contact between people. When the population grows to the peak that productivity can bear, people's living space will shrink sharply and the living environment will deteriorate sharply. Therefore, in the early days of human civilization, colonial activities were very frequent. The initial war was between those who opened up new living space and those who protected the old living space. Without these wars, people will be in a peaceful corner, population saturation will lead to the most basic survival problem, and science, technology, culture and economy will be greatly retrogressed and pulled back to the original state.

This is obvious. 1993 The genocide in Rwanda is the best proof. Population expansion and food shortage indirectly led to 100 people being slaughtered. The problems of human society are not waiting for human beings to solve, but will be solved by human hands.

In fact, even in Germany during World War II, it was the survival crisis caused by the economic crisis that triggered the massacre of Jews and even World War II. The same is true of Japan's invasion of China. If China's population is saturated, war is just around the corner.

Extinction should refer to environmental crisis, population expansion and excessive development, which will lead to the inability of productivity to keep up with the degree of environmental deterioration and the inability to remedy the ecological balance. Many civilizations that have been in a state of peaceful development for a long time are doomed to extinction, such as Maya, Easter Islander and Viking in Greenland. The American ecologist jared diamond's book Collapse fully explains this problem. He believes that the extreme imbalance of ecology is the ultimate cause of the demise of human civilization.