What is the law according to which the dosage of a herbal prescription is arrived at?

Hello, people say god doctor, god doctor, my understanding is that the diagnosis of the disease is accurate, the medicine is appropriately matched, and the dosage is right. It is used on the patient just right. The size of the dose is most critical. Just like a small horse pulling a big cart, a small one can't be pulled; a big horse pulling a small cart, pulls the cart apart. The patient's physique, living environment, and dietary habits are different, and so is the dose of the medicine. This is the most crucial part of TCM. People with one kind of disease, however, with a prescription, some work, some do not work. This is the reasoning. Make you laugh.