We call it "pigeon hole principle". When more than n objects are put in n drawers, at least one drawer has two or more objects.

If calculated in 70 years, the number of combinations with different sexes according to the date of birth should be 70× 365× 2 = 5 1 100, and we regard it as the number of drawers. The current population of China is 1 1 100 million, and we regard this figure as the number of "things". Because1.1× = 2 1526× 51/kloc-0+21400, according to principle 2, it is more than 21526, although

In ancient China, people knew how to use the pigeon hole principle to expose the fallacy of birth. For example, in Qing Dynasty, Chen Qiyuan wrote in Notes on Leisure Zhai: "I don't believe in the theory of pushing the stars, thinking that one person is born at a time (note: one hour, two hours), and twelve people are born in one day, which is 4,320 people in terms of age. Counting a Jia (note: 60 years), there are only 259,200 people. Today, only one county is counted. During this period, when the princes were born, there must be people born at the same time. What is the difference between the rich and the poor? " Here, a year is calculated as 360 days, and a day is divided into 12 hours, and the number of drawers obtained is 60× 360× 12 = 259200. The so-called "computer fortune-telling" is nothing more than storing the manually compiled fortune-telling sentences in their respective cabinets in advance like Chinese medicine cabinets. Who wants to tell fortune, that is, according to the different combinations of birth date, date and gender, according to different codes, mechanically take out the so-called fate sentence from the computer cabinet. It is blasphemy to put the aura of modern science on the dead who were superstitious in ancient times.