Is the eight-character calculation accurate before and blind after?

Whether it can be said that the previous measurement is accurate and the later measurement is not accurate only reflects the level of the forecaster, not the change of his own personality. This character has never changed. What should I do before and after? For example, I want to measure the weather now. Of course I know whether it was sunny or rainy in the past week. I will infer the weather in the next few days according to the weather these days, and the general accuracy will be higher, right? It was sunny a few days ago, so the chances of sunny days in the next few days are great. ) But something unexpected happened. It may have been sunny a few days ago, but it will rain cats and dogs tomorrow. At this time, I was wrong. In fact, no matter whether I predict whether it will be sunny or rainy in the next few days, the weather will not change because of my prediction. What is wrong is only my prediction, which will not have the slightest impact on the facts. In other words, forecasters face this fate just as I face this weather. For a forecaster, it is as easy to calculate the past as I know the weather the other day. But the weather in the next few days will not change because of my forecast, and the same constellation will not change because of the forecaster's forecast. The fate of the eight characters has always been there, unwavering and unchanged. No matter how others predict, it just runs according to its own rules. Therefore, even if the forecaster is accurate in predicting what happened before and inaccurate in predicting what happened after, it cannot be said that fate can be changed. Is it doomed that fate has never been changed? I don't know if I'm right.