Some people may ask that when the Pythagorean School initially tried to confirm whether √2 is a rational number, they did not know that √2 is not a rational number. In this case, could you ask: √2 can be written in the form of the simplest fraction? The author's answer is: this question is unreasonable. The reason is that since the arguer does not know whether √2 is a rational number, how can we ensure that this question will not be a complex question?