“Letting nature take its course” is a philosophy and a principle of psychotherapy, and the treatment principle of Morita-therapy is “letting nature take its course, and doing what is necessary”. It means to eliminate conflicts in the mind, to cultivate and exercise the emotions of the suspected disease quality, to get rid of the concept of disease, and to apply measures in accordance with the psychological conditions such as attention and emotion, so that the patient can experience nature in accordance with his/her symptoms and experience. In layman’s terms, we should regard some of our own thoughts and emotions as “normal”, “reasonable”, and “natural”, and should not always try to resist them. On the basis of “acceptance”, we should apply some methods and measures to adjust ourselves. Cao Rifang, Department of Clinical Psychology, Mental Health Center, School of Medicine, Zhejiang University, “let nature take its course” is not to leave the problem unattended, but to “make what should be there into something that must be there”. One’s emotions cannot be controlled by one’s own power. If one tries to be happy when he/she wants to cry, he/she will be forced to do so, and if he/she tries to be sad when he/she is extremely happy, he/she will not be able to do so either. If you do not run away from emotions that cannot be controlled by your own power, you should accept them as they come, and take action to do what you need to do, and that is “letting nature take its course”. On the other hand, even if you want to cry, if you are attending a friend’s wedding, you must smile no matter what, and this is also going with the flow. Morita therapy theory requires us to accept and embrace worry as a natural human emotion, and not to try to eliminate it as a foreign object; otherwise, it will lead to contradictions in thought and mental interactions due to “unattainability,” resulting in intense conflict in the inner world. If we can accept all the symptoms, pain, anxiety, worry and other emotions in a natural way, and silently bear and endure the pain brought about by these, we can be freed from the mechanism of being bound, and eliminate or avoid the negative aspects of the neurotic personality, and give full play to its positive effects. Therefore, the idea of “letting nature take its course” emphasizes the importance of not simply eliminating symptoms as a goal, but rather freeing oneself from repeated attempts to eliminate symptoms and then readjusting one’s life. Remember: “Instead of expecting and being able to eliminate your symptoms immediately, learn to live with them.” “If one has the demeanor of a healthy person, one will naturally be mentally healthy.”