“Self-contradiction” is a familiar idiomatic story, and the man who sold spears and shields has been talked about as a joke for thousands of years. However, in real life, sometimes they are not such a person? Often a doctor to the patient to boast that: I practiced medicine × × years, has never occurred a misdiagnosis or omission of cases, said the people are very serious, listening to the people are in awe, God doctor ah! But does such a “god doctor” exist? In fact, the miracle doctor is just a floating cloud, he is like the shield and spear mentioned in the idiomatic story, it is simply something unreal. People with a little bit of mathematical common sense know that if too much emphasis is placed on not being able to miss a diagnosis, there is bound to be a higher rate of misdiagnosis, which means that quite a number of people who are not sick are diagnosed by the doctor as patients; so what will happen if the opposite is done to ensure that no misdiagnosis can occur? What would happen if the opposite were true? The rate of misdiagnosis would be much higher, meaning that some sick people would be treated as if they were not sick. A good doctor can only find a balance between the rate of misdiagnosis and misdiagnosis, and minimize the occurrence of misdiagnosis and misdiagnosis, and there is no such thing as a doctor who never misses a diagnosis. On the other hand, medicine is a complex science, and in reality mankind knows no more about itself than it does about the moon. AIDS was discovered only thirty years ago, does it mean that there was no AIDS fifty years ago? At that time, many AIDS patients were most likely treated as other known diseases, according to the current popular saying of patients to doctors, “you delayed my illness, you misdiagnosed me and mistreated me”. So far, how many diseases have not been recognized by us is still a mystery, there is a very famous words in the medical profession: sometimes, to cure, often, to help, always, to comfort, which is actually the real portrayal of the doctor, even if the modern medicine has made great progress, but unfortunately can cure the disease is still very little, the doctor is more to give the patient as much as possible to help and comfort. The healer is more interested in giving the patient as much help and comfort as possible. So when we go to the doctor, we should keep a calm mind to communicate with the doctor and seek their help. Doctors who do not have a clear diagnosis of the disease may not be “quacks”, and those who guarantee a cure for all diseases of the doctor is certainly not a real healer, should cause patients to be vigilant. “God doctor” really does not exist, and misdiagnosis and missed diagnosis is certainly exist, in order to minimize the possibility of misdiagnosis and missed diagnosis, it is best to go to a regular hospital, for complex diseases, try to find specialists, refer to the views of multiple doctors!