(2) Occurrence of Posterior Force
When background organs of the stomach raise their momenta simultaneously, they cause a posterior force that can oppress the stomach. When background organs of the stomach raise their momenta simultaneously, they cause the imbalance in momentum with the stomach. This imbalance in momentum works as a force, which oppresses the stomach. Then, by this force, the stomach raises the momentum, and amplifies the initial distortion which has already caused in the stomach wall. Just this force indicates a posterior force that can oppress the stomach.
Interestingly, in this case, although the stomach only relatively reduces the momentum compared with the background field, it appears to raise the momentum for itself. Certainly, it is not the stomach but the background field to firstly change the momentum. However, the background field usually has large volume compared with the stomach. Thus, nevertheless the stomach in this condition only relatively reduces the momentum compared with the background field, it appears to reduce the momentum for itself. By this mechanism, this stomach starts raising the momentum to neutralize the imbalance in momentum with the background field.
Notice that such a special characteristic of posterior force prevents us from finding out the existence of posterior force. Even when an organ oppressed by posterior force raises the momentum, it appears to raise the momentum for itself. Additionally, the majority of medical examinations have been made only to find out where strong change occurs; in contrast, organs causing posterior force only show weak change. Thus, by using medical examinations, even when medical doctors can succeed in finding out an organ showing strong change, they will be unable not only to determine whether the fundamental cause originates in the organ or in the background organs, but also to ascertain the existence of posterior force. However, posterior force certainly exists in a human body, and plays a major role in causing various kinds of diseases including gastric scirrhus. In fact, the recognition of posterior force is indeed important to analyze diseases, especially serious ones.